Cloning of the p53 tumor suppressor gene from the Japanese medaka (Oryzias latipes) and evaluation of mutational hotspots in MNNG-exposed fish

A full-length cDNA clone of the medaka (Oryzias latipes) p53 tumor suppressor gene was isolated from a cDNA library from adult liver tissue? sequenced and characterized. Sequence analysis revealed a high degree of homology between putative functional domains of medaka p53 and p53 genes from other vertebrate taxa including rainbow trout (Oncorhynchus mykiss), frog (Xenopus laevis), chicken (Gallus gallus), rat (Rattus norvegicus), mouse (Mus musculus), hamster (Mesocricetus auratus), green monkey (Ceropithecus aethiops) and human (Homo sapiens). A single 1.9-kb p53 mRNA is expressed at a very low level in normal adult liver tissue. This transcript is similar in size to transcripts of p53 genes from other species. Preliminary screening of six MNNG-induced tumors in four adult medaka revealed no mutations within characteristic mutational hotspots encompassing conserved domains IV and V. (C) 1997 Elsevier Science B.V.