Cloning and sequence analysis of human genomic DNA of augmenter of liver regeneration.

The liver is one of the organs, which have potential regenerative capability in mammalian animal[1]. The study of the canine model indicated that the liver could regenerate to original size after 70% hepatectomy in only two weeks[2]. So it is a hot research topic for the cellular and molecular mechanism of liver regeneration. Accumulated results demonstrated that the hepatocyte growth factor (HGF)[3], insulin-like growth factor I and II (IGF-I, II)[4], epidermal growth factor (EGF), transforming growth factor alpha (TG F alpha)[5] and insulin[6] are among the most important growth factors for liver regenerative regulation. In recent years, a heat-stable protein in the serum of the patients with various liver diseases has been noted for its potential stimulation effects on the liver regeneration, and this growth factor is called hepatocyte-stimulatory substance (HSS). Gradient purification and sequence analysis of HSS protein indicated that the HSS protein itself is the augmenter of liver regeneration (ALR)[7], or called hepatopoietin (HPO)[8]. The immunohistochemical staining indicated that the expression of the ALR mainly existed in platelets and the sperm cells in testes, and ALR also could be found in the liver and the spleen which contain many platelets[9]. The analysis of the protein structure of the human and mouse ALR indicated that the primary protein structure of ALR does not contain a typical signal peptide sequence, and it is unknown if a specific receptor is necessary for the effect of the ALR. Therefore, it is important to clone the genomic DNA sequence of the ALR and it is also very helpful for the analysis of the structure of the ALR genomic DNA and regulation at the transcriptional and post-transcriptional levels.