Nucleotide sequence of mouse Tcp-1a cDNA.

We have isolated complete cDNA clones encoding the mouse t-complex polypeptides 1A and 1B (TCP-1A and TCP-1B) from t-haplotype and wild-type (wt) mice, respectively. The complete nucleotide (nt) sequence of the Tcp-1a cDNA was determined. The Tcp-1a cDNA has an open reading frame (ORF) encoding a 60-kDa protein of 556 amino acids (aa). A comparison of nt sequences between the Tcp-1a and Tcp-1b cDNAs revealed that the 1786-bp regions upstream from their polyadenylation signals differed by 17 substitutions and that Tcp-1a had different polyadenylation sites from Tcp-1b. In these ORFs, 15 bp were substituted between the two alleles, occurring in 14 codons and resulting in eleven single-aa substitutions. Among these 15 substitutions, twelve were nonsynonymous (aa change) and three were synonymous (no aa change). The aa substitution in TCP-1 has occurred at least 20 times faster between t-haplotype and wt than between mouse and human or mouse and Drosophila.