HP8: The cDNA clone of a novel member of C/EBP gene family

ＨＰ８：ＴｈｅｃＤＮＡｃｌｏｎｅｏｆａｎｏｖｅｌｍｅｍｂｅｒｏｆＣ／ＥＢＰｇｅｎｅｆａｍｉｌｙ￥（徐砺新）（万大方）（刘彦仿）（李宏年）（张萍萍）（隋延仿）（顾健人）ＸｕＬｉｘｉｎ，ＷａｎＤａｆａｎｇ，ＬｉｕＹａｎｆａｎｇ，ＬｉＨｏｎｇｎｉａｎ，Ｚｈ...

HP8: The cDNA clone of a novel member of C/EBP gene family

We obtained a positive clone by screening human fetal liver cDNA library with rat C/EBP cDNA probe.The clone , designated HPS , contains 2480 base pairs , 1026 of which are coding base pairs (from No. 84 to 1109).No homologous DNA sequence is found in the Gene Database (EMBL 95. 6) . The 341 amino acids encoded by HPS gene contained the leucine zipper structure at the Cterminal. They presented a high degree of homology (97%) to CIEBP throughout the DNA-binding domain and leucine repeat region(C-terminal 60 amino acids) , but in the upstream coding region , only a low degree of homology was detected to C/EBP or its related proteins , suggesting HPS is a novel member of CIEBP gene family. Southern blot analysis confirmed that HP8 gene was a single copy gene. Northern blot analysis of 14 different fetus tissues showed that HPS gene registered a high level expression in small intestine and skin , a middle level expression in adrenal ,a low level expression in liver , lung , kidney ,thyroid gland and gallbladder. Of 5 normal human adult liver tissues , only two were found to have low level HP8expression , whereas in 13 hepatoma and its surrounding nontumorous hepatic tissues , high level of HPS expression was detected in 9 hepatomas and 7 surrounding nontumorous hepatic tissues. These results suggest that HP8 gene may be a transactivator related to cell growth. A deeper research of its functions is now in progress.