The diverged copy of the citrus tristeza virus coat protein is expressed in vivo.

Nucleotide sequence analysis of a portion of the citrus tristeza closterovirus (CTV) genome revealed an open reading frame immediately upstream of the coat protein gene that can encode a protein with a calculated M(r) of 27,360 (p27). The deduced amino acid sequence indicated that this putative nonstructural gene product is highly homologous to the coat protein. To investigate whether p27 was expressed in CTV-infected plants, a fusion protein of p27 produced in Escherichia coli was used to raise polyclonal antibodies. Western blot analysis using the p27 antibodies indicated that p27 is expressed in CTV-infected citrus, but not in uninfected plants. Tissue fractionation studies revealed that p27 accumulates in cell wall enriched fractions.