| Autor: |
Fine, Mira, Sakal, Edna, Vashdi, Dorit, Daniel, Violet, Levanon, Avigdor, Lipshitz, Orli, Gertler, Arieh |
| Zdroj: |
General and Comparative Endocrinology; January 1993, Vol. 89 Issue: 1 p51-61, 11p |
| Abstrakt: |
Carp growth hormone (cGH) cDNA (Koren et al., 1989) was cloned under the control of λ-phage PLOL promoter and λcll ribosomal binding site into pBR322 plasmid to enable its expression in Escherichia coli A1645 that produces constitutively the thermolabile λ repressor c1857. Temperature shift to 42° abolished the repression, resulting in a high level of cGH expression. The bacterially expressed cGH protein, contained within the refractile body pellet, was solubilized in 4.5 M urea, refolded, and purified on Q-Sepharose column by stepwise elution with NaCl. The bioactive fraction was eluted at 0.2 M NaCl at a yield of 10-15%. This fraction contained predominantly (95%) 21.5-kDa monomeric cGH. The activity of cGH in vitro was bioassayed using Nb2-11C lymphoma cells (containing lactogenic receptors) and 3T3-F442A preadipocyte cells (containing somatogenic receptors). Bioactivity was found to be 0.01 and 6-10% that of human GH, respectively. In vivo cGH activity was measured by weekly ip injection in juvenille carp fed a low (23%) protein diet. Over a 6-week period, cGH increased the growth rate by 38% compared to fish injected with vehicle only. Identical injections with bovine GH yielded only a 21% increase. Copyright 1993, 1999 Academic Press |
| Databáze: |
Supplemental Index |
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