Two Tcp-1-related but highly divergent gene families exist in oat encoding proteins of assumed chaperone function

Tcp-1-related sequences have been isolated from a cDNA library of etiolated 6-day-old oat (Avena sativa) seedlings. This attempt was made to obtain cDNAs of a recently published 60 kDa plant chaperone that re-folds denatured phytochrome and which was biochemically characterised as a Tcp-1-related protein [(1993) Nature 363, 644-647]. The translation of the putative coding sequence from one full-length cDNA clone displays no specific homologies to amino acid sequences known from peptide sequencing of the oat 60 kDa chaperone. Antibodies raised against the 60 kDa chaperone and over-expressed protein from one full-length coding sequence for Tcp-1 from oat show no cross-reactivity, whereas a monoclonal antibody raised against mouse Tcp-1 protein recognizes both the 60 kDa protein purified from plant extracts and over-expressed protein from Tcp-1-related cDNA sequences.