THE MURINE FHIT LOCUS - ISOLATION, CHARACTERIZATION, AND EXPRESSION IN NORMAL AND TUMOR-CELLS

The murine Fhit locus maps near the centromere v proximal Ptprg Locus on mouse chromosome 14. The cDNA sequence and structure are similar to those of the human gene, with exons 5-9 encoding the protein. The pre dominant mRNA in the tissues and cell lines tested was an alternativel y spliced form missing exon 3. Most murine cell lines tested, includin g lines established from normal mouse embryos and tumors, expressed ve ry low or undetectable levels of Fhit mRNA. Most normal mouse tissues expressed wild-type Fhit mRNA, whereas similar to 40% of murine lung c arcinomas expressed wild-type and aberrant Fhit RT-PCR products that l acked various exons. Several tumorigenic mouse cell lines exhibited ho mozygous deletions of Fhit exons. We conclude that the murine Fhit gen e, like its human counterpart, is a target of alterations involved in murine carcinogenesis.