A complete rat serum albumin cDNA clone directly identified by immunological screening of cDNA expression library.

A CDNAexpression library was constructed from rat liver poly(A)+RNA by the vector primer and tailed linker methods using an Escherichia coli expression vector pKEN601[K.Nakamura, Y. Iwasaki and T. Hattori, Gene, 44, 347 (1986)].Immunological screening of this library with specific antibody against rat serum albumin identified a colony which carried a plasmid with a CDNAinsert of 2. 15 kilobases (kb).Restriction enzyme mapping and DNAsequencing analyses indicated that this CDNA clone carries a complete length rat serum albumin CDNA, and the 5'-terminus of the CDNA is in the potential capping site of the corresponding nuclear gene sequence. Full-lengthCDNA covering the entire coding region of the mRNAis especially useful for finding the primary structure of polypeptides and for the synthesis of polypeptides in large quantities using appropriate expression vectors.The identification of CDNA