Hepatocyte Nuclear factors-1 alpha, -1 beta, and -3 beta expressed in the gonad of tilapia (Oreochromis mossambicus)

Hepatocyte nuclear factors (HN-Fs) are upstream regulators of many liver-sp ecific genes and are involved in many cellular functions in the body, but t heir existence, expression, and function in gonads are still poorly underst ood. Here we report on the first cloning of partial cDNAs of HNF-1 alpha an d -1 beta and full HNF-3 beta cDNA from a tilapia (Oreochromis mossambicus) liver cDNA library. The deduced amino acid sequence of tilapia HNF-3 beta has a 90 to 96% identity with those of other fishes (dwarf gourami, medaka, and zebrafish), 75% with mammals (human, rat, and mouse), and 82% with Xen opus. RT-PCR detected IGF-I and -II and HNF-1 alpha, -1 beta, and -3 beta i n both liver and gonads and the identity of the PCR fragments was confirmed by PCR hybridization. Immunoprecipitation and Western blotting also detect ed all three HNF proteins in both liver and gonads. Expression of HNFs in t he gonads of the tilapia suggests that multi-HNFs may form a cascade to reg ulate gonadal physiology in the bony fish. (C) 2001 Academic Press.