Studies On The Expression Of Codon Optimized Human Growth Hormone In Escherichia Coli And Secreting Expression Of Human Growth Hormone In Pichia Pastoris

Human growth hormone(hGH) is a non-glycosylated protein secreted episodically by the anterior pituitary somatotrophs . It plays an important role in the human growth and development. The main fuction of hGH is to promote human growth and development and to maintain the routine fuction of the tissue and organ. People with hGH deficiency will suffer from dwarf and degeneration and function decline of tissue and organ. HGH is also widely used in the treatment of diseases such as burn, bone fracture, trauma, hemorrhagic ulcer, tissue necrosis, amyotrophia, osteoporosis and obesity. In order to improve the protein expression level of hGH in Escherichia coli, the coding sequence of hGH was optimized on the condition that the amino acid sequence of hGH was kept unchanging. At the same time, because Pichia pastoris has many advantages, it was used as the expression system to study the expression level of the interested gene to establish a platform of Pichia pastoris expression system and provide a useful tool for the large-scal production of hGH.The thesis mainly includes three parts:1. Synthesis and cloning of codon optimized hGH2. The expression of codon optimized hGH in E.coli3. Secreting expression of hGH in P. pastorisThe detailed results and conclusions are as follows:1. According to the amino acids and by selecting high-usage codons in E. coli, wedesigned and synthesized 20 oligonucleitides DNA fragments with the length about 55bp. By overlap extension PCR method, we successfully synthesized the entire sequence of hGH. The clones of interest were identified by DNA sequencing. The result showed that we had successfully accomplished the synthesis and cloning of hGH.