STRUCTURAL ORGANIZATION OF THE PORCINE AND HUMAN GENES-CODING FOR A LEYDIG CELL-SPECIFIC INSULIN-LIKE PEPTIDE (LEY I-L) AND CHROMOSOMAL LOCALIZATION OF THE HUMAN GENE (INSL3)

Leydig insulin-like protein (LEY I-L) is a member of the insulin-like hormone superfamily. The LEY I-L gene (designated INSL3) is expressed exclusively in prenatal and postnatal Leydig cells. We report here the cloning and nucleotide sequence of porcine and human LEY I-L genes in cluding the 5' regions. Both genes consist of two exons and one intron . The organization of the LEY I-L gene is similar to that of insulin a nd relaxin. The transcription start site in the porcine and human LEY I-L gene is localized 13 and 14 bp upstream of the translation start s ite, respectively. Alignment of the 5' flanking regions of both genes reveals that the first 107 nucleotides upstream of the transcription s tart site exhibit an overall sequence similarity of 80%. This conserve d region contains a consensus TATAA box, a CAAT-like element (GAAT), a nd a consensus SP1 sequence (GGGCGG) at equivalent positions in both g enes and therefore may play a role in regulation of expression of the LEY I-L gene. The porcine and human genome contains a single copy of t he LEY I-L gene. By in situ hybridization, the human gene was assigned to bands p13.2-p12 of the short arm of chromosome 19. (C) 1994 Academ ic Press, Inc.