Searching the human genome database for novel relaxin- and insulin-like peptides

In recent times, new members of the insulin/relaxin peptidesuperfamily have been identified by both differential cloningstrategies as well as bioinformatic searching of the ESTdatabases. We have used the public and Celera Genomicsdatabases to search for novel members of this peptide family.No new members of the insulin/relaxin family were identifiedalthough the human (H3) and mouse (M3) relaxin 3 genes that werecently discovered in the Celera Genomics database wereidentified in the public database. We were able to confirmthat there are no mouse equivalents of human INSL4 or humangene 1 relaxin. Hence, as the two human relaxin genes (H1 andH2) are localized together with INSL6 and INSL4 on chromosome9 it is probable that INSL4 and H1 relaxin are the result of agene duplication which did not occur in non-primates. Thediscovery of a full relaxin 3 sequences in a new Zebrafishbrain EST library, which retains a high homology in both A andB chain peptide sequence with the H3 peptide, indicate thatthis novel peptide has important conserved functions.