| comparative sequence of the helper component (hc) region of potato virus y and a hc-defective strain, potato virus c. | potato virus c (pvc), a non-aphid transmissible strain of potato virus y (pvy), was found to code for a protein (pvc-hc) which is similar in molecular weight and immunological reactivity to the helper component protein of pvy (pvy-hc). pvc-hc, however, was inactive with respect to its ability to effect aphid transmission of either pvc or pvy. the 5'-terminal 2.7-kb regions of pvc and pvy were sequenced. within the hc region there was 92% nucleotide homology between the two strains; comparison of ... | 1990 | 2219708 |
| mutations in zucchini yellow mosaic virus helper component protein associated with loss of aphid transmissibility. | zucchini yellow mosaic virus (zymv) is a potyvirus transmitted by aphids in a non-persistent manner. isolates having partially or totally lost their ability to be transmitted by aphids have been isolated and found to be affected in their helper component activities. we have sequenced the helper component coding region of poorly aphid-transmissible (pat) variants of two strains of zymv, e15 and r5a. mutations have been identified at the nucleotide level leading to two amino acid changes in the e1 ... | 1993 | 8277279 |
| mutations in the potyvirus helper component protein: effects on interactions with virions and aphid stylets. | mutations of k --> e in the highly conserved 'kitc' motif of the potyvirus helper component (hc) protein result in loss of hc function in aphid transmission, presumably because of inability to interact with virions, stylets or both. in this study we show that hc of potato virus c (pvc), a naturally occurring variant of potato virus y (pvy) that has the k --> e mutation, lacks the ability to be retained in stylets, whereas pvy hc is retained. the k --> e mutation in either pvc or a site-directed ... | 1998 | 9880030 |