Molecular Cloning, Expression, Separation And Purification Of Hepatopoietin Protein Cn(HPPCn) And Research On Its Bioactivity.

Although mammal's capacity of tissue regeneration is limited, the mammalian liver possesses a remarkable capacity of regeneration. Under normal circumstances, the human liver initiates regeneration within 3 days and reached its original size by 3-6 months. In most cases, liver function is restored to almost normal level within 3-6 weeks after Partial Hepatectomy(PH). The molecular mechanism of liver regeneration is always one of hot areas, which was concerned by many researchers in last several decades. There are about 1.2 hundred million patients with viral hepatitis, liver cirrhosis and liver cancer in China, so it is significant to comprehend the mechanism of liver regeneration and to develop specific drugs against hepatic injury.Research on regulation of liver regeneration could date from 70 years ago, in 1931 Higgins and Anderson described the process of rat liver generation after PH. In 1975, La Brecque et al first reported that in the liver of weanling rat or in the liver after PH, there existed a kind of substance, named HSS, which was found to be a specific stimulator of hepatic DNA synthesis both in vivo and in vitro. During past 30 years, the physicochemical characteristics, purification and bioactivity of HSS from mammals and human were investigated. From 1980s, human HSS, which could stimulate liver growth and be effective in improving survival of rat with CCl₄-induced acute liver failure, was named hepatopoietin(HPO). In 1995, HPO was approved for USA patent. In our laboratory, Cui et al. currently purified three proteins with specific growth stimulating activity from the fetal bovine liver. One of them has been verified to be a member of the leucine-rich acidic nuclear protein family by Q-TOF. A typical member of human LANP family is pp32, which was highly expressed in renewable tissue and involved in various cellular processes including regulation of transcription, development, and intracellular signaling .