Basic Research
Copyright ©The Author(s) 2002. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Apr 15, 2002; 8(2): 353-356
Published online Apr 15, 2002. doi: 10.3748/wjg.v8.i2.353
Identification and characterization of a novel isoform of hepatopoietin
Jun Lu, Wang-Xiang Xu, Yi-Qun Zhan, Xiao-Lin Cui, Wei-Min Cai, Fu-Chu He, Xiao-Ming Yang
Jun Lu, Wei-Min Cai, Institute of Infectious Disease, First Affiliated Hospital, Medical School, Zhejiang University, Hangzhou 310003 China
Wang-Xiang Xu, Yi-Qun Zhan, Xiao-Lin Cui, Fu-Chu He, Xiao-Ming Yang, Institute of Radiation Medicine, Academy of Military Medical Sciences, Beijing 100850, China
Author contributions: All authors contributed equally to the work.
Supported by the National Natural Science Foundation of China, No. 39830440
Correspondence to: Dr. Xiao-Ming Yang, Institute of Radiation Medicine, Academy of Military Medical Sciences, Beijing 100850, China. xiaomingyang@sina.com.cn
Telephone: +86-10-66931424 Fax: +86-10-68214653
Received: September 14, 2001
Revised: November 7, 2001
Accepted: November 14, 2001
Published online: April 15, 2002
Abstract

AIM: To isolate a novel isoform of human HPO (HPO-205) from human fetal liver Marathon-ready cDNA and characterize its primary biological function.

METHODS: 5'-RACE (rapid amplification of cDNA 5’ends) was used to isolate a novel isoform of hHPO in this paper. The constructed pcDNAHPO-205, pcDNAHPO and pcDNA eukaryotic expression vectors were respectively transfected by lipofectamine method and the stimulation of DNA synthesis was observed by 3H-TdR incorporation assay. Proteins extracted from different cells were analyzed by Western blot.

RESULTS: A novel isoform of hHPO (HPO-205) encoding a 205 amino acid ORF corresponding to a translated production of 23 kDa was isolated and distinguished from the previous HPO that lacked the N-terminal 80 amino acids. The dose-dependent stimulation of DNA synthesis of HepG2 hepatoma cells by HPO-205 demonstrated its similar biological activity with HPO in vitro. The level of MAPK (Mitogen-activated protein kinase) phosphorylation by Western blot analysis revealed that HPO-205 might have the stronger activity of stimulating hepatic cell proliferation than that of HPO.

CONCLUSION: A novel isoform of hHPO (HPO-205) was isolated from hepatic-derived cells. The comparison of HPO-205 and HPO will lead to a new insight into the structure and function of hHPO, and provide the new way of thinking to deeply elucidate the biological roles of HPO/ALR.

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