CHARACTERIZATION OF THE TOBACCO EIF-4A GENE FAMILY

Characterization of cDNAs encoding eukaryotic translation initiation f actor 4A (eIF-4A) indicates the expression of a minimum of ten related genes in tobacco leaf cells. The ten groups fall into two gene famili es, NeIF-4A2 and NeIF-4A3. The majority of the cDNAs exhibit significa nt sequence similarity to the NeIF-4A2 family at both the DNA and dedu ced amino acid levels. Northern analysis using specific probes indicat es variable expression of four family members in various tobacco organ s. Western analysis, using an anti-tobacco eIF-4A polyclonal antibody, reveals a complex pattern of immunologically related polypeptides of approximately 46 kDa. Subcellular fractionation suggests that at least one eIF-4A-related polypeptide is located in the chloroplast where it is ribosome-associated.