CLONING OF LL5, A NOVEL PROTEIN-ENCODING CDNA FROM A RAT PITUITARY LIBRARY

While screening a rat pituitary cDNA library for a peptide hormone rec eptor, we identified a cDNA that represents a novel gene. The 3.8 kb c DNA has an open reading frame of 2.3 kb encoding a protein of 781 amin o acids (M, = 87507). Southern blot analysis of rat, mouse, bovine and human genomic DNAs revealed that a homologous gene is present in thes e species probably in a single copy. Northern blot analysis showed tha t in addition to the pituitary gland, the gene is also expressed in ot her rat tissues. Scanning of DNA and protein databanks revealed no sig nificant homology to any other sequence. Thus, this gene encodes a her etofore unidentified protein.