| clonal analysis of cardiac morphogenesis in the chicken embryo using a replication-defective retrovirus. iii: polyclonal origin of adjacent ventricular myocytes. | replication-incompetent variants of the avian spleen necrosis virus (snv) encoding cytoplasmic or nuclear-directed beta-galactosidase (beta-gal) have been used to trace the clonal growth of myocytes during left ventricular free-wall formation. tubular-stage hearts were infected with a mixed suspension of both retroviruses and, after hatching, the progeny of marked cells in the ventricular wall were examined by x-gal histochemistry. when a small number of virions was introduced individual blue pa ... | 1992 | 1297456 |
| novel gacg-hairpin pair motif in the 5' untranslated region of type c retroviruses related to murine leukemia virus. | we searched for the presence of common rna structural motifs in mammalian type c retroviruses related to murine leukemia viruses and the closely related avian spleen necrosis virus. a novel motif consisting of a pair of hairpins, called hairpin pair motif, was detected in the 5' untranslated regions of the genomes of these retroviruses. a combination of computational analyses that included the assessment of phylogenetic sequence conservation by multiple alignment, the search for regions with unu ... | 1992 | 1309906 |
| in vivo analysis of a new lacz retrovirus vector suitable for cell lineage marking in avian and other species. | to obtain a replication-defective retrovirus vector well suited for cell lineage marking in early avian embryos, we have constructed and tested a derivative of the avian spleen necrosis virus (snv) carrying the marker gene lacz. consistently high titers of this virus, designated cxl, were produced from retroviral packaging cells with no evidence of contaminating helper virus even after 12 months of continuous culture. cxl expresses lacz strongly and stably in avian cells and has a host range tha ... | 1991 | 2070832 |
| sequence instability in the long terminal repeats of avian spleen necrosis virus and reticuloendotheliosis virus. | sequence divergence between the 3' long terminal repeats (ltr) of avian reticuloendotheliosis virus (rev), deletion variant proviral clone 2-20-4, and spleen necrosis virus (snv)-proviral clones 14-44, 60, and 70-was found to involve two classes of base substitutions: low-frequency interspersed and high-frequency clustered substitutions. clones 2-20-4 and 14-44 have diverged 4.4% owing to low-frequency substitutions. in contrast, two high-frequency substitution segments have diverged by 30% and ... | 1987 | 2822937 |
| terminal repeats of the drosophila transposable element copia: nucleotide sequence and genomic organization. | we have determined the nucleotide sequence of the terminal regions of two members of the copia sequence family of d. melanogaster. the first 276 bp at one end of a copia element are repeated in direct orientation at its other end. the direct repeats on a single copia element are identical to each other, but they differ by two nucleotide substitutions between the two elements which were examined; this suggests that during transposition only one direct repeat of the parent element is used as a tem ... | 1980 | 6250726 |
| 5'-terminal nucleotide noncoding sequences of retroviruses: relatedness of two old world primate type c viruses and avian spleen necrosis virus. | computer-assisted comparison of the 5'-terminal regions of mammalian type c viruses serves as a useful model of evolutionary divergence of noncoding nucleic acid sequences. it has led to the concept that regions of conserved nucleic acid sequences, the slowly divergent sequences, contain signals of translational, transcriptional, or integrative significance. interspersed among the conserved regions are rapidly divergent sequences in which base changes, insertions, and deletions are especially pr ... | 1981 | 6268813 |
| characterization of an internal ribosomal entry segment within the 5' leader of avian reticuloendotheliosis virus type a rna and development of novel mlv-rev-based retroviral vectors. | the murine leukemia virus (mlv)-related type c viruses constitute a major class of retroviruses that includes numerous endogenous and exogenous mammalian viruses and the related avian spleen necrosis virus (snv). the mlv-related viruses possess a long and multifunctional 5' untranslated leader involved in key steps of the viral life cycle--splicing, translation, rna dimerization, encapsidation, and reverse transcription. recent studies have shown that the 5' leader of friend murine leukemia viru ... | 1997 | 9382952 |
| targeted gene transfer to lymphocytes using murine leukaemia virus vectors pseudotyped with spleen necrosis virus envelope proteins. | in contrast to murine leukaemia virus (mlv)-derived vector systems, vector particles derived from the avian spleen necrosis virus (snv) have been successfully targeted to subsets of human cells by envelope modification with antibody fragments (scfv). however, an in vivo application of the snv vector system in gene transfer protocols is hampered by its lack of resistance against human complement. to overcome this limitation we established pseudotyping of mlv vector particles produced in human pac ... | 2001 | 11509952 |