Expression, subcellular location and modification of the 50 kDa protein encoded by ORF2 of the apple chlorotic leaf spot trichovirus genome.

A putative movement protein of molecular mass 50 kDa encoded by the ORF2 of the apple chlorotic leaf spot virus (ACLSV) genome was expressed in Escherichia coli using an expression vector and was then used to produce an antiserum. Immunoblot analysis using an antiserum raised against this protein showed that the ORF2 protein of ACLSV was detected in both cell wall and cell membrane fractions prepared from infected Chenopodium quinoa tissues. The ORF2 protein from infected tissues had a molecular mass of 52 kDa, larger than that of the full-length ORF2 protein (50 kDa protein) expressed in E. coli. Incubation of the 52 kDa protein with alkaline phosphatase resulted in a decrease in its apparent molecular mass from 52 kDa to 50 kDa, strongly suggesting that the ORF2 protein of ACLSV is phosphorylated in infected plant tissues.