Nucleotide sequence of the zucchini yellow mosaic virus capsid-encoding gene and its expression in Escherichia coli.

Zucchini yellow mosaic virus (ZYMV) RNA was purified and used as a template for the synthesis of cDNA. A partial restriction map covering 9.4 kb of the ZYMV genome was constructed from three clones designated ZYKS-22, ZYKS-16 and ZYKS-3. Sequencing the 3'-end region of the ZYMV genome indicates the presence of (A)48 chain. This is followed by an untranslated region of 210 nucleotides (nt) and a coding region of 837 nt corresponding to the putative virus coat protein (Cp) gene (cp). The predicted amino acid (aa) sequence of Cp derived from the cDNA showed about 50% to 62% homology with the known aa sequence for Cp of six other potyviruses. A construct of the putative cp was subcloned in frame with the lacZp gene promoter in a Bluescript plasmid and expressed in Escherichia coli cells. The fusion polypeptides (34 and 41 kDa), positively reacted in Western blots with an antiserum prepared against the native virus Cp.