Construction Of Vectors For The Overexpression Of Recombinant Human Growth Hormone In Bacillus Megaterium

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Date
2009-01
Authors
Abd. Rashid, Norhashima
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Publisher
Universiti Sains Malaysia
Abstract
In order to express the hGH gene in Bacillus megaterium, 3 constructs were designed. The constructs were named as Construct 1 (M7hGH), Construct 2 (R2L4sphGH) and Construct 3 (spBsubhGH). Construct 1 was designed with regulatory features [stop codon, ribosome binding site (RBS), TAACA sequence and start codon] meant for intracellular expression. Construct 2, was created to express human growth hormone (hGH) extracellularly by using the signal peptide from Bacillus brevis. For Construct 3, the signal peptide from B. subtilis CU1065 was used to express hGH extracellularly but the regulatory gene [stop codon, ribosome binding site (RBS) and start codon between xylA protein and hGH] was excluded to create a fusion protein combining xylA and the hGH gene. However, no expressions were obtained from Construct 1 and 2 probably due to the presence of unfavourable codons. The synthetic hGH gene contains 10 arginine codons (AGA) (4.8%) in which the frequency is much higher than the 1.7% AGA and 0.9% AGG estimated for E. coli. Construct 3 yielded an unidentified ~20 kDa protein and further analysis is required to identify the protein. The average percentage of cells carrying plasmid was calculated among these 3 constructs in order to determine the plasmid stability For Construct 1 (M7hGH), the average rate of reduction of cells that carry plasmid is 10% for each generation, Construct 2 (R2L4sphGH) is 5% for each generation and Construct 3 (spBsubhGH) is 4.8% for each generation.
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Keywords
Vectors For The Overexpression , Recombinant Human Growth Hormone In Bacillus Megaterium
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