SUBCELLULAR LOCATION AND EXPRESSION OF TOBACCO NECROSIS NECROVIRUS P7A PROTEIN

A putative movement protein (p7a) of tobacco necrosis Necrovirus, stra in D (TNV-D), produced in Escherichia coli using an expression vector, was used to raise an antiserum. Immunoblot analysis using this antise rum showed that the p7a protein was detectable only in the combined ce ll wall and cell membrane fraction prepared from TNV-D infected Phaseo lus vulgaris leaves. The p7a protein was detectable 1 day after inocul ation and reached a maximum 3 days later, before declining, whereas co at protein was not detectable until 3 days after inoculation and conti nued to increase in concentration for a further 2 days before declinin g. Differences in the detectable amounts of both proteins may reflect their differential stability in extracts from necrotic tissue and/or t he transient expression of the putative movement protein early in the replication cycle of TNV-D.