Cloning of the capsid protein gene from a blotch isolate of peanut stripe virus.

The 3' terminal 1,367 nucleotides (nts) of a blotch isolate of the potyvirus, peanut stripe virus (PStV), were cloned and sequenced. This region included the 861 nts (287 amino acids) of the PStV capsid protein (CP). The amino acid sequence of the predicted proteinase cleavage site was identified. This region shared limited homology with other potyvirus proteinase cleavage sites. The viral CP gene sequence was followed by 254 nucleotides of 3' nontranslated sequence and a poly-A tail. Based on computer modeling, the 3' nontranslated region could form two lengthy stem-loop structures and two pseudoknot structures. Subclones containing the coding sequences of the CP (amino acids 1-287, 17-287, 17-113 and 106-287) were constructed and expressed in Escherichia coli. These polypeptides were detected using polyclonal antibodies in Western blots.