Isolation and Sequence Analysis of Bovine α_s1-Casein cDNA Clone

抄録

Poly(A⁺) RNAwas isolated from lactating cow mammary gland and cDNAwas synthesized by a method which resulted in a high yield of products containing complete 5'-terminal mRNAsequences. Transformants were screened with a HaelU-EcoRI fragment for bovine α_s1-casein CDNA[M. Maki, M. Nagao, M. Hirose and H. Chiba, Agric. Biol Chem., 47, 441 (1983)]. A CDNAclone was isolated that contained the full length of α_s1-casein mRNAand its nucleotide sequence was determined. The amino acid sequence predicted from the nucleotide sequence was in good agreement with that determined with the purified mature α_s1-casein. The signal peptide consisting of 15 amino acids was identical to that of ovine α_s1-casein. High homology at the nucleotide sequence level in the signal peptide region and in the 5'-untranslated region was found between rat α-casein and bovine α_s1-casein.