Publications

pathological features of olfactory neuroblastoma in an axolotl (ambystoma mexicanum).	a one-year-old, female mexican axolotl (ambystoma mexicanum) had a rough-surfaced, polypoid, pink tumor mass of approximately 10 mm in diameter in the oral cavity. histologically, the tumor extended from the ethmoturbinate region and into the oral cavity and had replaced some of the maxillary bone tissue. the tumor mass was composed of a lobular architecture of small round-shaped tumor cells with occasional flexner-wintersteiner-like rosette formation. there were no metastatic lesions in the oth ...	2011	21519157
blastema induction in aneurogenic state and prrx-1 regulation by mmps and fgfs in ambystoma mexicanum limb regeneration.	urodele amphibians can regenerate amputated limbs. it has been considered that differentiated dermal tissues generate multipotent and undifferentiated cells called blastema cells during limb regeneration. in early phases of limb regeneration, blastema cells are induced by nerves and the apical epithelial cap (aec). we had previously investigated the role of neurotrophic factors in blastema or blastema-like formation consisting of prrx-1 positive cells. a new system suitable for investigating ear ...	2011	21539833
regeneration in vitro of axolotl peripheral and central axons.	peripheral nerves and spinal cords of axolotls were maintained in organ culture for periods of up to 2 weeks. sensory axons in peripheral nerves and the dorsal funiculus of the spinal cord showed regeneration through the crush site within about 2 days. axonal regeneration also occurred in peripheral nerves after cutting but was dependent on close contact between proximal and distal stumps of nerve. when cells in the distal stump of nerve were killed by freezing, axonal regeneration was inhibited ...	1990	21551566
the yeast two hybrid system in a screen for proteins interacting with axolotl (ambystoma mexicanum) msx1 during early limb regeneration.	urodele amphibians are exceptional in their ability to regenerate complex body structures such as limbs. limb regeneration depends on a process called dedifferentiation. under an inductive wound epidermis terminally differentiated cells transform to pluripotent progenitor cells that coordinately proliferate and eventually redifferentiate to form the new appendage. recent studies have developed molecular models integrating a set of genes that might have important functions in the control of regen ...	2011	21571103
absence of mutation at the 5'-upstream promoter region of the tpm4 gene from cardiac mutant axolotl (ambystoma mexicanum).	tropomyosins are a family of actin-binding proteins that show cell-specific diversity by a combination of multiple genes and alternative rna splicing. of the 4 different tropomyosin genes, tpm4 plays a pivotal role in myofibrillogenesis as well as cardiac contractility in amphibians. in this study, we amplified and sequenced the upstream regulatory region of the tpm4 gene from both normal and mutant axolotl hearts. to identify the cis-elements that are essential for the expression of the tpm4, w ...	2011	21626230
gene expression profile of the regeneration epithelium during axolotl limb regeneration.	urodele amphibians are unique among adult vertebrates in their ability to regenerate missing limbs. the process of limb regeneration requires several key tissues including a regeneration-competent wound epidermis called the regeneration epithelium (re). we used microarray analysis to profile gene expression of the re in the axolotl, a mexican salamander. a list of 125 genes and expressed sequence tags (ests) showed a ≥1.5-fold expression in the re than in a wound epidermis covering a lateral cuf ...	2011	21648017
the meis homeoprotein regulates the axolotl prod 1 promoter during limb regeneration.	during limb regeneration in salamanders the blastemal cells give rise only to structures distal to the level of amputation. this proximodistal identity can be regulated by ectopic expression of meis homeoproteins or the three finger protein prod 1 which acts at the cell surface. it has been suggested that meis acts by regulating the transcription of prod 1. we have sequenced the axolotl prod 1 promoter and selected two candidate sites for binding meis homeoproteins. the sites were mutated in var ...	2011	21684325
a system for culturing iris pigment epithelial cells to study lens regeneration in newt.	salamanders like newt and axolotl possess the ability to regenerate many of its lost body parts such as limbs, the tail with spinal cord, eye, brain, heart, the jaw¹. specifically, newts are unique for its lens regeneration capability. upon lens removal, ipe cells of the dorsal iris transdifferentiate to lens cells and eventually form a new lens in about a month²(,)³ . this property of regeneration is never exhibited by the ventral iris cells. the regeneration potential of the iris cells can be ...	2011	21730940
the cellular basis for animal regeneration.	the ability of animals to regenerate missing parts is a dramatic and poorly understood aspect of biology. the sources of new cells for these regenerative phenomena have been sought for decades. recent advances involving cell fate tracking in complex tissues have shed new light on the cellular underpinnings of regeneration in hydra, planarians, zebrafish, xenopus, and axolotl. planarians accomplish regeneration with use of adult pluripotent stem cells, whereas several vertebrates utilize a collec ...	2011	21763617
molecular and biochemical characterization of the mexican axolotl cd3 (cd3ε and cd3γ/δ).	in mammals, the t-cell receptor (tcr) complex expressed on mature t-cells consists of α/β or γ/δ clonotypic heterodimers non-covalently associated with four invariant chains forming the cd3 complex (cd3γ, cd3δ, cd3ε and cd3ζ). the tcr is the unit implicated in the antigenic peptide recognition whereas the cd3 subunits present as three different dimers (δ-ε, γ-ε and ζ-ζ) in the receptor complex participate to the signal transduction and are indispensable for the expression of the tcr at the cell ...	2011	21789595
immersion and branchial/transcutaneous irrigation anaesthesia with alfaxalone in a mexican axolotl.	immersion anaesthetic techniques are commonly used in amphibian species. alfaxalone has been reported as an immersion anaesthetic in fish but not amphibians.	2011	21988819
electrosensory ampullary organs are derived from lateral line placodes in bony fishes.	electroreception is an ancient subdivision of the lateral line sensory system, found in all major vertebrate groups (though lost in frogs, amniotes and most ray-finned fishes). electroreception is mediated by 'hair cells' in ampullary organs, distributed in fields flanking lines of mechanosensory hair cell-containing neuromasts that detect local water movement. neuromasts, and afferent neurons for both neuromasts and ampullary organs, develop from lateral line placodes. although ampullary organs ...	2011	21988912
esterases activity in the axolotl ambystoma mexicanum exposed to chlorpyrifos and its implication to motor activity.	the axolotl ambystoma mexicanum is a neotenic salamander considered a good biological model due to its ability to regenerate limbs, tail, brain and heart cells. nevertheless, severe reduction of a. mexicanum wild populations in the lacustrine area of xochimilco, the natural habitat of the axolotl, could be related to several environmental pressures as the presence of organophosphate pesticides (opps), intensively applied in agricultural activities in xochimilco. thus the aim of this study was to ...	2011	21996259
histology of plastic embedded amphibian embryos and larvae.	amphibians including the south african clawed frog xenopus laevis, its close relative xenopus tropicalis, and the mexican axolotl (ambystoma mexicanum) are important vertebrate models for cell biology, development, and regeneration. for the analysis of embryos and larva with altered gene expression in gain-of-function or loss-of-function studies histology is increasingly important. here, we discuss plastic or resin embedding of embryos as valuable alternatives to conventional paraffin embedding. ...	2011	22083609
CXCL14-like immunoreactivity in growth hormone-containing cells of urodele pituitaries.	Immunohistochemical techniques were employed to investigate the distribution of a chemokine, namely, CXCL14-like immunoreactivity in the axolotl (Ambystoma mexicanum) and Japanese black salamander (Hynobius nigrescens) pituitaries. CXCL14-immunoreactive cells concentrated at an area of the pars distalis adjacent to the pars intermedia. We found that these cells correspond to the cells immunoreactive to an antibody against rat growth hormone (GH). Immunoelectron microscopy indicated that the CXCL ...	2011	22119756
ambiguities in the relationship between gonadal steroids and reproduction in axolotls (ambystoma mexicanum).	axolotls (ambystoma mexicanum) are aquatic salamanders that are widely used in research. axolotls have been bred in laboratories for nearly 150 years, yet little is known about the basic biology of reproduction in these animals. we investigated the effects of changing day length, time of year, and food availability on levels of circulating estradiol and androgens in adult female and male axolotls, respectively. in addition, we examined the effects of these variables on the mass of ovaries, ovidu ...	2012	22245262
the amazing, regenerating axolotl.		2012	22261883
elaphoidella grandidieri (harpacticoida: copepoda): demographic characteristics and possible use as live prey in aquaculture.	in freshwater ecosystems, rotifers and cladocerans are ideal prey for fish larvae whereas copepods, due to their purported low growth rate and predatory tendency, are not. we recently isolated the parthenogenetic elaphoidella grandidieri (gueme et richard, 1893) a benthic freshwater harpacticoid, from a fish farm in the state of morelos, central mexico and tested its potential as a live prey organism for larval vertebrates. population growth and life table demography experiments were conducted, ...	2011	22315830
cell movements of the deep layer of non-neural ectoderm underlie complete neural tube closure in xenopus.	in developing vertebrates, the neural tube forms from a sheet of neural ectoderm by complex cell movements and morphogenesis. convergent extension movements and the apical constriction along with apical-basal elongation of cells in the neural ectoderm are thought to be essential for the neural tube closure (ntc) process. in addition, it is known that non-neural ectoderm also plays a crucial role in this process, as the neural tube fails to close in the absence of this tissue in chick and axolotl ...	2012	22378637
collagen reconstitution is inversely correlated with induction of limb regeneration in ambystoma mexicanum.	amphibians can regenerate missing body parts, including limbs. the regulation of collagen has been considered to be important in limb regeneration. collagen deposition is suppressed during limb regeneration, so we investigated collagen deposition and apical epithelial cap (aec) formation during axolotl limb regeneration. the accessory limb model (alm) has been developed as an alternative model for studying limb regeneration. using this model, we investigated the relationship between nerves, epid ...	2012	22379987
semi-quantitative immunohistochemical detection of 5-hydroxymethyl-cytosine reveals conservation of its tissue distribution between amphibians and mammals.	5-hydroxymethyl-cytosine (5-hmc) is a form of modified cytosine, which has recently attracted a considerable attention due to its potential role in transcriptional regulation. according to several reports 5-hydroxymethyl-cytosine distribution is tissue-specific in mammals. thus, 5-hmc is enriched in embryonic cell populations and in adult neuronal tissue. here, we describe a novel method of semi-quantitative immunohistochemical detection of 5-hmc and utilize it to assess the levels of this modif ...	2012	22395462
skin regeneration in adult axolotls: a blueprint for scar-free healing in vertebrates.	while considerable progress has been made towards understanding the complex processes and pathways that regulate human wound healing, regenerative medicine has been unable to develop therapies that coax the natural wound environment to heal scar-free. the inability to induce perfect skin regeneration stems partly from our limited understanding of how scar-free healing occurs in a natural setting. here we have investigated the wound repair process in adult axolotls and demonstrate that they are c ...	2012	22485136
muscle development and differentiation in the urodele ambystoma mexicanum.	muscle differentiation has been widely described in zebrafish and xenopus, but nothing is known about this process in amphibian urodeles. both anatomical features and locomotor activity in urodeles are known to show intermediate features between fish and anurans. therefore, a better understanding of myogenesis in urodeles could be useful to clarify the evolutionary changes that led to the formation of skeletal muscle in the trunk of land vertebrates. we report here a detailed morphological and m ...	2012	22519643
partial characterization of the sox2+ cell population in an adult murine model of digit amputation.	tissue regeneration in response to injury in adult mammals is generally limited to select tissues. nonmammalian species such as newts and axolotls undergo regeneration of complex tissues such as limbs and digits via recruitment and accumulation of local and circulating multipotent progenitors preprogrammed to recapitulate the missing tissue. directed recruitment and activation of progenitor cells at a site of injury in adult mammals may alter the default wound-healing response from scar tissue t ...	2012	22530556
nerve signaling regulates basal keratinocyte proliferation in the blastema apical epithelial cap in the axolotl (ambystoma mexicanum).	the ability of adult vertebrates to repair tissue damage is widespread and impressive; however, the ability to regenerate structurally complex organs such as the limb is limited largely to the salamanders. the fact that most of the tissues of the limb can regenerate has led investigators to question and identify the barriers to organ regeneration. from studies in the salamander, it is known that one of the earliest steps required for successful regeneration involves signaling between nerves and ...	2012	22537500
visualization of retinoic acid signaling in transgenic axolotls during limb development and regeneration.	retinoic acid (ra) plays a necessary role in limb development and regeneration, but the precise mechanism by which it acts during these processes is unclear. the role of ra in limb regeneration was first highlighted by the remarkable effect that it has on respecifying the proximodistal axis of the regenerating limb so that serially repeated limbs are produced. to facilitate the study of ra signaling during development and then during regeneration of the same structure we have turned to the axolo ...	2012	22627291
cranial muscles in amphibians: development, novelties and the role of cranial neural crest cells.	our research on the evolution of the vertebrate head focuses on understanding the developmental origins of morphological novelties. using a broad comparative approach in amphibians, and comparisons with the well-studied quail-chicken system, we investigate how evolutionarily conserved or variable different aspects of head development are. here we review research on the often overlooked development of cranial muscles, and on its dependence on cranial cartilage development. in general, cranial mus ...	2013	22780231
structural and functional analysis of intra-articular interzone tissue in axolotl salamanders.	knowledge of mechanisms directing diarthrodial joint development may be useful in understanding joint pathologies and identifying new therapies. we have previously established that axolotl salamanders can fully repair large articular cartilage lesions, which may be due to the presence of an interzone-like tissue in the intra-articular space. study objectives were to further characterize axolotl diarthrodial joint structure and determine the differentiation potential of interzone-like tissue in a ...	2012	22800772
reconstitution of the central and peripheral nervous system during salamander tail regeneration.	we show that after tail amputation in ambystoma mexicanum (axolotl) the correct number and spacing of dorsal root ganglia are regenerated. by transplantation of spinal cord tissue and nonclonal neurospheres, we show that the central spinal cord represents a source of peripheral nervous system cells. interestingly, melanophores migrate from preexisting precursors in the skin. finally, we demonstrate that implantation of a clonally derived spinal cord neurosphere can result in reconstitution of al ...	2012	22829665
spatiotemporal regulation of keratin 5 and 17 in the axolotl limb.	amphibians have greater regeneration capability than higher vertebrates. they can regenerate their limbs after an amputation. as a limb is regenerated, a regeneration-specific epithelium called the apical epithelial cap (aec) is induced. the aec is an essential structure for limb regeneration. despite the importance of the aec, molecular marker genes have not been well studied at the molecular level.	2012	22836940
activation of germline-specific genes is required for limb regeneration in the mexican axolotl.	the capacity for tissue and organ regeneration in humans is dwarfed by comparison to that of salamanders. emerging evidence suggests that mechanisms learned from the early phase of salamander limb regeneration-wound healing, cellular dedifferentiation and blastemal formation-will reveal therapeutic approaches for tissue regeneration in humans. here we describe a unique transcriptional fingerprint of regenerating limb tissue in the mexican axolotl (ambystoma mexicanum) that is indicative of cellu ...	2012	22841627
inducible genetic system for the axolotl.	transgenesis promises a powerful means for assessing gene function during amphibian limb regeneration. this approach is complicated, however, by the need for embryonic appendage development to proceed unimpeded despite the genetic alterations one wishes to test later in the context of regeneration. achieving conditional gene regulation in this amphibian has not proved to be as straightforward as in many other systems. in this report we describe a unique method for obtaining temporal control over ...	2012	22869739
retrotransposon long interspersed nucleotide element-1 (line-1) is activated during salamander limb regeneration.	salamanders possess an extraordinary capacity for tissue and organ regeneration when compared to mammals. in our effort to characterize the unique transcriptional fingerprint emerging during the early phase of salamander limb regeneration, we identified transcriptional activation of some germline-specific genes within the mexican axolotl (ambystoma mexicanum) that is indicative of cellular reprogramming of differentiated cells into a germline-like state. in this work, we focus on one of these ge ...	2012	22913491
reconstitution of the central nervous system during salamander tail regeneration from the implanted neurospheres.	urodele amphibians such as axolotl are well known for their regenerative potential of the damaged central nervous system structures. upon tail amputation, neural stem cells behind the amputation plane undergo self-renewing divisions and contribute to the functional spinal cord in the newly formed regenerate. the neural stem cells, harboring this potential, can be isolated from the animal and cultured under the suspension conditions. after 2-3 weeks in vitro they will proliferate and form the flo ...	2012	22914942
early regulation of axolotl limb regeneration.	amphibian limb regeneration has been studied for a long time. in amphibian limb regeneration, an undifferentiated blastema is formed around the region damaged by amputation. the induction process of blastema formation has remained largely unknown because it is difficult to study the induction of limb regeneration. the recently developed accessory limb model (alm) allows the investigation of limb induction and reveals early events of amphibian limb regeneration. the interaction between nerves and ...	2012	22933482
histone deacetylases are required for amphibian tail and limb regeneration but not development.	amphibians such as xenopus laevis and ambystoma mexicanum are capable of whole structure regeneration. however, transcriptional control over these events is not well understood. here, we investigate the role of histone deacetylase (hdac) enzymes in regeneration using hdac inhibitors. the class i/ii hdac inhibitor valproic acid (vpa) inhibits tail regeneration in embryos of the anuran amphibian xenopus laevis, confirming a recent report by others (tseng et al., 2011). this inhibition correlates w ...	2015	22947425
anatomy of the pectoral and forelimb muscles of wildtype and green fluorescent protein-transgenic axolotls and comparison with other tetrapods including humans: a basis for regenerative, evolutionary and developmental studies.	the axolotl ambystoma mexicanum is one of the most used model organisms in evolutionary, developmental and regenerative studies, particularly because it can reconstitute a fully functional and complete forelimb/hindlimb. surprisingly, there is no publication that describes all the pectoral and forelimb muscles of this species or provides a comparative framework between these muscles and those of other model organisms and of modern humans. in the present paper we describe and illustrate all these ...	2012	22957800
evolution of electrosensory ampullary organs: conservation of eya4 expression during lateral line development in jawed vertebrates.	the lateral line system of fishes and amphibians comprises two ancient sensory systems: mechanoreception and electroreception. electroreception is found in all major vertebrate groups (i.e. jawless fishes, cartilaginous fishes, and bony fishes); however, it was lost in several groups including anuran amphibians (frogs) and amniotes (reptiles, birds, and mammals), as well as in the lineage leading to the neopterygian clade of bony fishes (bowfins, gars, and teleosts). electroreception is mediated ...	2017	23017075
neuropeptide y enhances olfactory mucosa responses to odorant in hungry rats.	neuropeptide y (npy) plays an important role in regulating appetite and hunger in vertebrates. in the hypothalamus, npy stimulates food intake under the control of the nutritional status. previous studies have shown the presence of npy and receptors in rodent olfactory system, and suggested a neuroproliferative role. interestingly, npy was also shown to directly modulate olfactory responses evoked by a food-related odorant in hungry axolotls. we have recently demonstrated that another nutritiona ...	2012	23024812
microarray analysis of microrna expression during axolotl limb regeneration.	among vertebrates, salamanders stand out for their remarkable capacity to quickly regrow a myriad of tissues and organs after injury or amputation. the limb regeneration process in axolotls (ambystoma mexicanum) has been well studied for decades at the cell-tissue level. while several developmental genes are known to be reactivated during this epimorphic process, less is known about the role of micrornas in urodele amphibian limb regeneration. given the compelling evidence that many micrornas ti ...	2012	23028429
a galvanotaxis assay for analysis of neural precursor cell migration kinetics in an externally applied direct current electric field.	the discovery of neural stem and progenitor cells (collectively termed neural precursor cells) (npcs) in the adult mammalian brain has led to a body of research aimed at utilizing the multipotent and proliferative properties of these cells for the development of neuroregenerative strategies. a critical step for the success of such strategies is the mobilization of npcs toward a lesion site following exogenous transplantation or to enhance the response of the endogenous precursors that are found ...	2012	23093363
muscle and connective tissue progenitor populations show distinct twist1 and twist3 expression profiles during axolotl limb regeneration.	limb regeneration involves re-establishing a limb development program from cells within adult tissues. identifying molecular handles that provide insight into the relationship between cell differentiation status and cell lineage is an important step to study limb blastema cell formation. here, using single cell pcr, focusing on newly isolated twist1 sequences, we molecularly profile axolotl limb blastema cells using several progenitor cell markers. we link their molecular expression profile to t ...	2013	23103585
5-carboxylcytosine is localized to euchromatic regions in the nuclei of follicular cells in axolotl ovary.	5-methylcytosine (5-mc) is an epigenetic modification associated with gene repression. recent studies demonstrated that 5-mc can be enzymatically oxidised into 5-hydroxymethylcytosine and further into 5-formylcytosine (5-fc) and 5-carboxylcytsine (5-cac). 5-cac has been found in embryonic stem cells and in mouse pre-implantation embryos but no detectable levels of this modification have been reported for somatic tissues to date. whereas it has been suggested that 5-cac can serve as an intermedia ...	2017	23138778
association of modified cytosines and the methylated dna-binding protein mecp2 with distinctive structural domains of lampbrush chromatin.	we have investigated the association of dna methylation and proteins interpreting methylation state with the distinctive closed and open chromatin structural domains that are directly observable in the lampbrush chromosomes (lbcs) of amphibian oocytes. to establish the distribution in lbcs of mecp2, one of the key proteins binding 5-methylcytosine-modified dna (5mc), we expressed ha-tagged mecp2 constructs in xenopus laevis oocytes. full-length mecp2 was predominantly targeted to the closed, tra ...	2012	23149574
prominent role of prominin in the retina.	prominin molecules represent a new family of pentaspan membrane glycoproteins expressed throughout the animal kingdom. the name originates from its localization on membrane protrusion, such as microvilli, filopodia, lamellipodia, and microspikes. following the original description in mouse and human, representative prominin members were found in fish (e.g., danio rerio), amphibian (ambystoma mexicanum, xenopus laevis), worm (caenorhabditis elegans), and flies (drosophila melanogaster). mammalian ...	2013	23161075
regeneration of limb joints in the axolotl (ambystoma mexicanum).	in spite of numerous investigations of regenerating salamander limbs, little attention has been paid to the details of how joints are reformed. an understanding of the process and mechanisms of joint regeneration in this model system for tetrapod limb regeneration would provide insights into developing novel therapies for inducing joint regeneration in humans. to this end, we have used the axolotl (mexican salamander) model of limb regeneration to describe the morphology and the expression patte ...	2012	23185640
gene expression patterns specific to the regenerating limb of the mexican axolotl.	salamander limb regeneration is dependent upon tissue interactions that are local to the amputation site. communication among limb epidermis, peripheral nerves, and mesenchyme coordinate cell migration, cell proliferation, and tissue patterning to generate a blastema, which will form missing limb structures. an outstanding question is how cross-talk between these tissues gives rise to the regeneration blastema. to identify genes associated with epidermis-nerve-mesenchymal interactions during lim ...	2012	23213371
reprogramming to pluripotency is an ancient trait of vertebrate oct4 and pou2 proteins.	the evolutionary origins of the gene network underlying cellular pluripotency, a central theme in developmental biology, have yet to be elucidated. in mammals, oct4 is a factor crucial in the reprogramming of differentiated cells into induced pluripotent stem cells. the oct4 and pou2 genes evolved from a pou class v gene ancestor, but it is unknown whether pluripotency induced by oct4 gene activity is a feature specific to mammals or was already present in ancestral vertebrates. here we report t ...	2012	23232409
lens regeneration in axolotl: new evidence of developmental plasticity.	among vertebrates lens regeneration is most pronounced in newts, which have the ability to regenerate the entire lens throughout their lives. regeneration occurs from the dorsal iris by transdifferentiation of the pigment epithelial cells. interestingly, the ventral iris never contributes to regeneration. frogs have limited lens regeneration capacity elicited from the cornea during pre-metamorphic stages. the axolotl is another salamander which, like the newt, regenerates its limbs or its tail w ...	2012	23244204
cell cycle regulation and regeneration.	regeneration of ear punch holes in the mrl mouse and amputated limbs of the axolotl show a number of similarities. a large proportion of the fibroblasts of the uninjured mrl mouse ear are arrested in g2 of the cell cycle, and enter nerve-dependent mitosis after injury to form a ring-shaped blastema that regenerates the ear tissue. multiple cell types contribute to the establishment of the regeneration blastema of the urodele limb by dedifferentiation, and there is substantial reason to believe t ...	2013	23263201
wound healing in mammals and amphibians: toward limb regeneration in mammals.	mammalian fetal skin regenerates perfectly, but adult skin repairs by the formation of scar tissue. the cause of this imperfect repair by adult skin is not understood. in contrast, wounded adult amphibian (urodeles and anurans) skin is like mammalian fetal skin in that it repairs by regeneration, not scarring. scar-free wound repair in adult xenopus is associated with expression of the paired homeobox transcription factor prx1 by mesenchymal cells of the wound, a feature shared by mesenchymal ce ...	2013	23263248
connective tissue cells, but not muscle cells, are involved in establishing the proximo-distal outcome of limb regeneration in the axolotl.	during salamander limb regeneration, only the structures distal to the amputation plane are regenerated, a property known as the rule of distal transformation. multiple cell types are involved in limb regeneration; therefore, determining which cell types participate in distal transformation is important for understanding how the proximo-distal outcome of regeneration is achieved. we show that connective tissue-derived blastema cells obey the rule of distal transformation. they also have nuclear ...	2013	23293283
neural crest does not contribute to the neck and shoulder in the axolotl (ambystoma mexicanum).	a major step during the evolution of tetrapods was their transition from water to land. this process involved the reduction or complete loss of the dermal bones that made up connections to the skull and a concomitant enlargement of the endochondral shoulder girdle. in the mouse the latter is derived from three separate embryonic sources: lateral plate mesoderm, somites, and neural crest. the neural crest was suggested to sustain the muscle attachments. how this complex composition of the endocho ...	2012	23300623
proliferation zones in the axolotl brain and regeneration of the telencephalon.	although the brains of lower vertebrates are known to exhibit somewhat limited regeneration after incisional or stab wounds, the urodele brain exhibits extensive regeneration after massive tissue removal. discovering whether and how neural progenitor cells that reside in the ventricular zones of urodeles proliferate to mediate tissue repair in response to injury may produce novel leads for regenerative strategies. here we show that endogenous neural progenitor cells resident to the ventricular z ...	2013	23327114
revisiting the relationship between regenerative ability and aging.	contrary to the longstanding view that newts (notophthalamus viridescens), but not axolotls (ambystoma mexicanum), can regenerate a lens, a recent report in bmc biology by panagiotis tsonis and colleagues shows axolotls indeed possess this ability during early larval stages. in contrast, they show that zebrafish never posses this ability, even as embryos. this underscores the importance of comparing regenerative ability across species and reinforces the need to consider organ regeneration in the ...	2013	23336699
comparative pelvic development of the axolotl (ambystoma mexicanum) and the australian lungfish (neoceratodus forsteri): conservation and innovation across the fish-tetrapod transition.	the fish-tetrapod transition was one of the major events in vertebrate evolution and was enabled by many morphological changes. although the transformation of paired fish fins into tetrapod limbs has been a major topic of study in recent years, both from paleontological and comparative developmental perspectives, the interest has focused almost exclusively on the distal part of the appendage and in particular the origin of digits. relatively little attention has been paid to the transformation o ...	2013	23342976
pseudotyped retroviruses for infecting axolotl in vivo and in vitro.	axolotls are poised to become the premiere model system for studying vertebrate appendage regeneration. however, very few molecular tools exist for studying crucial cell lineage relationships over regeneration or for robust and sustained misexpression of genetic elements to test their function. furthermore, targeting specific cell types will be necessary to understand how regeneration of the diverse tissues within the limb is accomplished. we report that pseudotyped, replication-incompetent retr ...	2013	23344705
profiling neurotransmitter receptor expression in the ambystoma mexicanum brain.	ability to regenerate limbs and central nervous system (cns) is unique to few vertebrates, most notably the axolotl (ambystoma sp.). however, despite the fact the neurotransmitter receptors are involved in axonal regeneration, little is known regarding its expression profile. in this project, rt-pcr and qpcr were performed to gain insight into the neurotransmitter receptors present in ambystoma. its functional ability was studied by expressing axolotl receptors in xenopus laevis oocytes by eithe ...	2013	23353105
wound epithelium function in axolotl limb regeneration.	axolotls (ambystoma mexicanum) have the ability to regenerate amputated limbs. the amputation surface is promptly covered by wound epithelium (we), which is significant for the initiation of limb regeneration. in the present study, we investigated the formation of functional we by analyzing the migration of we after amputation. in the center of the amputation surface, epithelial cells migrated from surrounding epidermis to form we. therefore, we around the center of the amputation surface was co ...	2012	23429052
a hyperpolarization-activated ion current of amphibian oocytes.	a comparative analysis of a hyperpolarization-activated ion current present in amphibian oocytes was performed using the two-electrode voltage-clamp technique in xenopus laevis, xenopus tropicalis, and ambystoma mexicanum. this current appears to be driven mainly by cl(-) ions, is independent of ca(2+), and is made evident by applying extremely negative voltage pulses; it shows a slow activating phase and little or no desensitization. the pharmacological profile of the current is complex. the di ...	2013	23440457
an investigative laboratory exercise examining the cell signaling and regulatory properties of neurons in the regenerating forelimbs of the axolotl ambystoma mexicanum.	many students understand the electrical properties of neurons and can adequately describe the creation and transmission of electrical impulses. however, students often have difficulty when it comes to understanding how neurons have an equally important role in cell signaling. this latter function is crucial in the establishment of proper cell fate during regeneration. i have devised a lab that includes in its goals: 1) an investigation into the cell signaling role of neurons, 2) experience with ...	2005	23493055
comparative rna-seq analysis in the unsequenced axolotl: the oncogene burst highlights early gene expression in the blastema.	the salamander has the remarkable ability to regenerate its limb after amputation. cells at the site of amputation form a blastema and then proliferate and differentiate to regrow the limb. to better understand this process, we performed deep rna sequencing of the blastema over a time course in the axolotl, a species whose genome has not been sequenced. using a novel comparative approach to analyzing rna-seq data, we characterized the transcriptional dynamics of the regenerating axolotl limb wit ...	2013	23505351
a new unique form of microrna from human heart, microrna-499c, promotes myofibril formation and rescues cardiac development in mutant axolotl embryos.	a recessive mutation "c" in the mexican axolotl, ambystoma mexicanum, results in the failure of normal heart development. in homozygous recessive embryos, the hearts do not have organized myofibrils and fail to beat. in our previous studies, we identified a noncoding myofibril-inducing rna (mir) from axolotls which promotes myofibril formation and rescues heart development.	2013	23522091
regeneration of soft tissues is promoted by mmp1 treatment after digit amputation in mice.	the ratio of matrix metalloproteinases (mmps) to the tissue inhibitors of metalloproteinases (timps) in wounded tissues strictly control the protease activity of mmps, and therefore regulate the progress of wound closure, tissue regeneration and scar formation. some amphibians (i.e. axolotl/newt) demonstrate complete regeneration of missing or wounded digits and even limbs; mmps play a critical role during amphibian regeneration. conversely, mammalian wound healing re-establishes tissue integrit ...	2013	23527099
expression pattern of nogo-a, mag, and ngr in regenerating urodele spinal cord.	the mammalian central nervous system is incapable of substantial axon regeneration after injury partially due to the presence of myelin-associated inhibitory molecules including nogo-a and myelin associated glycoprotein (mag). in contrast, axolotl salamanders are capable of considerable axon regrowth during spinal cord regeneration.	2013	23592243
misexpression experiment of tbx5 in axolotl (ambystoma mexicanum) hindlimb blastema.	axolotls (ambystoma mexicanum) have the ability to regenerate amputated limbs throughout their life span. in the present study, we attempted to elucidate how axolotls can specify limb type correctly during the regeneration process. we misexpressed tbx5 in regenerating hindlimb blastema, and consequently a forelimb-like hindlimb regenerated from the hindlimb blastema. on the other hand, no change was observed in tbx5-overexpressing forelimb blastema, and thus we considered that tbx5 plays a key r ...	2013	23614983
lmx-1b and wnt-7a expression in axolotl limb during development and regeneration.	axolotls (ambystoma mexicanum) have the ability to regenerate amputated limbs throughout their life span. during limb regeneration as well as development, undifferentiated cells in the blastema acquire positional information to reproduce the original pattern along three cardinal limb axes: anteroposterior, proximodistal and dorsoventral. in the present study, we attempted to understand the molecular mechanism involved in patterning of axolotl limb development and regeneration along the dorsovent ...	2013	23614984
foamy virus for efficient gene transfer in regeneration studies.	molecular studies of appendage regeneration have been hindered by the lack of a stable and efficient means of transferring exogenous genes. we therefore sought an efficient integrating virus system that could be used to study limb and tail regeneration in salamanders.	2013	23641815
accessory limb induction on flank region and its muscle regulation in axolotl.	urodele amphibians have high regeneration capability that has been studied for a long time. recently, a new experimental system called the accessory limb model was developed and becomes alternative choice for amphibian limb regeneration study. although the accessory limb model has many advantages, an improvement was needed for some specific analysis, such as studying muscle origin. for that purpose, an accessory limb induction on nonlimb regions was attempted.	2013	23649747
cranial muscle development in the model organism ambystoma mexicanum: implications for tetrapod and vertebrate comparative and evolutionary morphology and notes on ontogeny and phylogeny.	there is still confusion about the homology of several cranial muscles in salamanders with those of other vertebrates. this is true, in part, because of the fact that many muscles present in early ontogeny of amphibians disappear during development and specifically during metamorphosis. resolving this confusion is important for the understanding of the comparative and evolutionary morphology of vertebrates and tetrapods because amphibians are the phylogenetically most plesiomorphic tetrapods, co ...	2013	23650269
concise review: pursuing self-renewal and pluripotency with the stem cell factor nanog.	pluripotent embryonic stem cells and induced pluripotent stem cells hold great promise for future use in tissue replacement therapies due to their ability to self-renew indefinitely and to differentiate into all adult cell types. harnessing this therapeutic potential efficiently requires a much deeper understanding of the molecular processes at work within the pluripotency network. the transcription factors nanog, oct4, and sox2 reside at the core of this network, where they interact and regulat ...	2013	23653415
comparative transcriptional profiling of the axolotl limb identifies a tripartite regeneration-specific gene program.	understanding how the limb blastema is established after the initial wound healing response is an important aspect of regeneration research. here we performed parallel expression profile time courses of healing lateral wounds versus amputated limbs in axolotl. this comparison between wound healing and regeneration allowed us to identify amputation-specific genes. by clustering the expression profiles of these samples, we could detect three distinguishable phases of gene expression - early wound ...	2013	23658691
complement-triggered pathways orchestrate regenerative responses throughout phylogenesis.	adult tissue plasticity, cell reprogramming, and organ regeneration are major challenges in the field of modern regenerative medicine. devising strategies to increase the regenerative capacity of tissues holds great promise for dealing with donor organ shortages and low transplantation outcomes and also provides essential impetus to tissue bioengineering approaches for organ repair and replacement. the inherent ability of cells to reprogram their fate by switching into an embryonic-like, pluripo ...	2013	23684626
macrophages are required for adult salamander limb regeneration.	the failure to replace damaged body parts in adult mammals results from a muted growth response and fibrotic scarring. although infiltrating immune cells play a major role in determining the variable outcome of mammalian wound repair, little is known about the modulation of immune cell signaling in efficiently regenerating species such as the salamander, which can regrow complete body structures as adults. here we present a comprehensive analysis of immune signaling during limb regeneration in a ...	2013	23690624
spatial distribution of prominin-1 (cd133)-positive cells within germinative zones of the vertebrate brain.	in mammals, embryonic neural progenitors as well as adult neural stem cells can be prospectively isolated based on the cell surface expression of prominin-1 (cd133), a plasma membrane glycoprotein. in contrast, characterization of neural progenitors in non-mammalian vertebrates endowed with significant constitutive neurogenesis and inherent self-repair ability is hampered by the lack of suitable cell surface markers. here, we have investigated whether prominin-1-orthologues of the major non-mamm ...	2013	23723983
nerve independent limb induction in axolotls.	urodele amphibians can regenerate their limbs. during limb regeneration, dermal fibroblasts are transformed into undifferentiated cells called blastema cells. these dermis-blastema cells show multipotency. such so-called endogenous reprogramming of cell differentiation is one of the main targets of amphibian limb regeneration studies. it is well recognized that nerve presence controls the initiation of limb regeneration. accordingly, nerve factors have been sought in amphibian limb regeneration. ...	2013	23769980
de novo transcriptome sequencing of axolotl blastema for identification of differentially expressed genes during limb regeneration.	salamanders are unique among vertebrates in their ability to completely regenerate amputated limbs through the mediation of blastema cells located at the stump ends. this regeneration is nerve-dependent because blastema formation and regeneration does not occur after limb denervation. to obtain the genomic information of blastema tissues, de novo transcriptomes from both blastema tissues and denervated stump ends of ambystoma mexicanum (axolotls) 14 days post-amputation were sequenced and compar ...	2013	23815514
body wall development in lamprey and a new perspective on the origin of vertebrate paired fins.	classical hypotheses regarding the evolutionary origin of paired appendages propose transformation of precursor structures (gill arches and lateral fin folds) into paired fins. during development, gnathostome paired appendages form as outgrowths of body wall somatopleure, a tissue composed of somatic lateral plate mesoderm (lpm) and overlying ectoderm. in amniotes, lpm contributes connective tissue to abaxial musculature and forms ventrolateral dermis of the interlimb body wall. the phylogenetic ...	2013	23818600
variation in salamander tail regeneration is associated with genetic factors that determine tail morphology.	very little is known about the factors that cause variation in regenerative potential within and between species. here, we used a genetic approach to identify heritable genetic factors that explain variation in tail regenerative outgrowth. a hybrid ambystomatid salamander (ambystoma mexicanum x a. andersoni) was crossed to an a. mexicanum and 217 offspring were induced to undergo metamorphosis and attain terrestrial adult morphology using thyroid hormone. following metamorphosis, each salamander ...	2013	23843997
molecular cloning, sequence analysis and homology modeling of the first caudata amphibian antifreeze-like protein in axolotl (ambystoma mexicanum).	antifreeze proteins (afps) refer to a class of polypeptides that are produced by certain vertebrates, plants, fungi, and bacteria and which permit their survival in subzero environments. in this study, we report the molecular cloning, sequence analysis and three-dimensional structure of the axolotl antifreeze-like protein (aflp) by homology modeling of the first caudate amphibian aflp. we constructed a full-length spleen cdna library of axolotl (ambystoma mexicanum). an est having highest simila ...	2013	23915159
genomics of a metamorphic timing qtl: met1 maps to a unique genomic position and regulates morph and species-specific patterns of brain transcription.	very little is known about genetic factors that regulate life history transitions during ontogeny. closely related tiger salamanders (ambystoma species complex) show extreme variation in metamorphic timing, with some species foregoing metamorphosis altogether, an adaptive trait called paedomorphosis. previous studies identified a major effect quantitative trait locus (met1) for metamorphic timing and expression of paedomorphosis in hybrid crosses between the biphasic eastern tiger salamander (am ...	2013	23946331
limb regeneration.	limb regeneration is observed in certain members of the animal phyla. some animals keep this ability during their entire life while others lose it at some time during development. how do animals regenerate limbs? is it possible to find unifying, conserved mechanisms of limb regeneration or have different species evolved distinct means of replacing a lost limb? how is limb regeneration similar or different to limb development? studies on many organisms, including echinoderms, arthropods, and chor ...	2016	24009038
gain-of-function assays in the axolotl (ambystoma mexicanum) to identify signaling pathways that induce and regulate limb regeneration.	the adult salamander has been studied as a model for regeneration of complex tissues for many decades. only recently with the development of gain-of-function assays for regeneration, has it been possible to screen for and assay the function of the multitude of signaling factors that have been identified in studies of embryonic development and tumorigenesis. given the conservation of function of these regulatory pathways controlling growth and pattern formation, it is now possible to use the func ...	2013	24029949
leucine-enkephalin-like immunoreactivity is localized in luteinizing hormone-producing cells in the axolotl (ambystoma mexicanum) pituitary.	in this study, we used immunohistochemical techniques to determine the cell type of leucine-enkephalin (leu-enk)-immunoreactive cells in the axolotl (ambystoma mexicanum) pituitary. immunoreactive cells were scattered throughout the pars distalis except for the dorso-caudal portion. these cells were immuno-positive for luteinizing hormone (lh), but they were immuno-negative for adrenocorticotrophic, growth, and thyroid-stimulating hormones, as well as prolactin. immunoelectron microscopy demonst ...	2014	24034715
germline transgenic methods for tracking cells and testing gene function during regeneration in the axolotl.	the salamander is the only tetrapod that regenerates complex body structures throughout life. deciphering the underlying molecular processes of regeneration is fundamental for regenerative medicine and developmental biology, but the model organism had limited tools for molecular analysis. we describe a comprehensive set of germline transgenic strains in the laboratory-bred salamander ambystoma mexicanum (axolotl) that open up the cellular and molecular genetic dissection of regeneration. we demo ...	2013	24052945
positional information is reprogrammed in blastema cells of the regenerating limb of the axolotl (ambystoma mexicanum).	the regenerating region of an amputated salamander limb, known as the blastema, has the amazing capacity to replace exactly the missing structures. by grafting cells from different stages and regions of blastemas induced to form on donor animals expressing green fluorescent protein (gfp), to non-gfp host animals, we have determined that the cells from early stage blastemas, as well as cells at the tip of late stage blastemas are developmentally labile such that their positional identity is repro ...	2013	24086768
resegmentation in the mexican axolotl, ambystoma mexicanum.	the segmental series of somites in the vertebrate embryo gives rise to the axial skeleton. in amniote models, single vertebrae are derived from the sclerotome of two adjacent somites. this process, known as resegmentation, is well-studied using the quail-chick chimeric system, but the presumed generality of resegmentation across vertebrates remains poorly evaluated. resegmentation has been questioned in anamniotes, given that the sclerotome is much smaller and lacks obvious differentiation betwe ...	2014	24127283
enzymatically active 2',5'-oligoadenylate synthetases are widely distributed among metazoa, including protostome lineage.	2',5'-oligoadenylate synthetases (oass) belong to the nucleotidyl transferase family together with poly(a) polymerases, cca-adding enzymes and the recently discovered cyclic-gmp-amp synthase (cgas). mammalian oass have been thoroughly characterized as components of the interferon-induced antiviral system. the oas activity and the respective genes were also discovered in marine sponges where the interferon system is absent. in this study the recombinant oass from several multicellular animals and ...	2014	24184688
molecular cloning, sequence analysis and phylogeny of first caudata g-type lysozyme in axolotl (ambystoma mexicanum).	lysozymes are key proteins that play important roles in innate immune defense in many animal phyla by breaking down the bacterial cell-walls. in this study, we report the molecular cloning, sequence analysis and phylogeny of the first caudate amphibian g-lysozyme: a full-length spleen cdna library from axolotl (ambystoma mexicanum). a goose-type (g-lysozyme) est was identified and the full-length cdna was obtained using race-pcr. the axolotl g-lysozyme sequence represents an open reading frame f ...	2013	24199859
development of fore- and hindlimb muscles in frogs: morphogenesis, homeotic transformations, digit reduction, and the forelimb-hindlimb enigma.	here we provide the first detailed description, based on immunohistochemistry and dissections, of the limb muscle development in the direct developing frog eleutherodactylus coqui. we compare e. coqui with other tetrapods and discuss our results in a broad evolutionary and developmental context to address some major questions concerning the origin, evolution, and ontogeny of the tetrapod limbs. our observations and comparisons: (1) support the "in-out" developmental mechanism of the appendicular ...	2014	24254979
fundamental differences in dedifferentiation and stem cell recruitment during skeletal muscle regeneration in two salamander species.	salamanders regenerate appendages via a progenitor pool called the blastema. the cellular mechanisms underlying regeneration of muscle have been much debated but have remained unclear. here we applied cre-loxp genetic fate mapping to skeletal muscle during limb regeneration in two salamander species, notophthalmus viridescens (newt) and ambystoma mexicanum (axolotl). remarkably, we found that myofiber dedifferentiation is an integral part of limb regeneration in the newt, but not in axolotl. in ...	2014	24268695
development of fore- and hindlimb muscles in gfp-transgenic axolotls: morphogenesis, the tetrapod bauplan, and new insights on the forelimb-hindlimb enigma.	the axolotl is becoming one of the most used model organisms in developmental and regenerative studies but no publication has described in detail the development of its forelimb and hindlimb muscles. we describe and illustrate the ontogeny of these muscles in transgenic axolotls that express gfp in muscle fibers and discuss our results and data previously obtained by us and by other authors about limb regeneration in axolotls and ontogeny in frogs and other tetrapods. our observations and compar ...	2014	24302552
is salamander hindlimb regeneration similar to that of the forelimb? anatomical and morphogenetic analysis of hindlimb muscle regeneration in gfp-transgenic axolotls as a basis for regenerative and developmental studies.	the axolotl ambystoma mexicanum is one of the most used model organisms in developmental and regenerative studies because it is commonly said that it can reconstitute a normal and fully functional forelimb/hindlimb after amputation. however, there is not a publication that has described in detail the regeneration of the axolotl hindlimb muscles. here we describe and illustrate, for the first time, the regeneration of the thigh, leg and foot muscles in transgenic axolotls that express green fluor ...	2014	24325444
progressive specification rather than intercalation of segments during limb regeneration.	an amputated salamander limb regenerates the correct number of segments. models explaining limb regeneration were largely distinct from those for limb development, despite the presence of common patterning molecules. intercalation has been an important concept to explain salamander limb regeneration, but clear evidence supporting or refuting this model was lacking. in the intercalation model, the first blastema cells acquire fingertip identity, creating a gap in positional identity that triggers ...	2013	24337297
conservation of position-specific gene expression in axolotl limb skin.	urodele amphibians can regenerate their limbs after amputation. after amputation, undifferentiated cells appear on the amputation plane and form regeneration blastema. a limb blastema recreates a complete replica of the original limb. it is well known that disturbance of the location of limb tissues prior to amputation perturbs limb patterning, suggesting that different intact limb tissues carry different location information despite their identical appearance. the cause of such differences in i ...	2014	24410490
optimized axolotl (ambystoma mexicanum) husbandry, breeding, metamorphosis, transgenesis and tamoxifen-mediated recombination.	the axolotl (mexican salamander, ambystoma mexicanum) has become a very useful model organism for studying limb and spinal cord regeneration because of its high regenerative capacity. here we present a protocol for successfully mating and breeding axolotls in the laboratory throughout the year, for metamorphosing axolotls by a single i.p. injection and for axolotl transgenesis using i-scei meganuclease and the mini tol2 transposon system. tol2-mediated transgenesis provides different features an ...	2014	24504478
axolotl as a model to study scarless wound healing in vertebrates: role of the transforming growth factor beta signaling pathway.	the skin is our largest organ, with the primary role of protection against assaults from the outside world. it also suffers frequent damage, from minor scrapes to, more rarely, complete destruction such as in third-degree burns. it is therefore, by its nature, an organ that would benefit tremendously from being able to regenerate itself.	2013	24527347
the effects of local x-ray irradiation on the tail development of young axolotls.		1950	24537002
dual embryonic origin of the hyobranchial apparatus in the mexican axolotl (ambystoma mexicanum).	traditionally, the cartilaginous viscerocranium of vertebrates is considered as neural crest (nc)-derived. morphological work carried out on amphibian embryos in the first half of the xx century suggested potentially mesodermal origin for some hyobranchial elements. since then, the embryonic sources of the hyobranchial apparatus in amphibians has not been investigated due to lack of an appropriate long-term labelling system. we performed homotopic transplantations of neural folds along with the ...	2013	24623073
two different network topologies yield bistability in models of mesoderm and anterior mesendoderm specification in amphibians.	understanding the gene regulatory networks (grns) that underlie development is a major question for systems biology. the establishment of the germ layers is amongst the earliest events of development and has been characterised in numerous model systems. the establishment of the mesoderm is best characterised in the frog xenopus laevis and has been well studied both experimentally and mathematically. however, the xenopus network has significant differences from that in mouse and humans, including ...	2014	24650939