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. © 1997 Elsevier Science B.V. All rights reserved.