TY - JOUR
T1 - Chimeric bovine-human growth hormone prepared by recombinant DNA technology
T2 - Binding properties and biological activity
AU - Binder, Lydia
AU - Vogel, Tikva
AU - Hadary, Dan
AU - Elberg, Gerard
AU - Gertler, Arieh
PY - 1989/6
Y1 - 1989/6
N2 - A chimeric bovine GH (amino acids Met-Asp-Gln->1-23) and human GH (hGH) (amino acids 24-191) plasmid was constructed and expressed in Escherichia coii. The purified protein (chimeric GH) exhibited a 2-3 order of magnitude lower affinity toward lactogenic receptors in Nb2 lymphoma cells, microsomal fractions from bovine mammary gland and male rat liver. The affinity towards somatogenic receptors in IM-9 human lymphocytes and male rat liver was decreased to a much lesser degree.This diminished affinity towards lactogenic receptors was accompanied by a parallel decrease in the ability of the chimeric GH to stimulate proliferation of Nb2-11C lymphoma cells and the lipogenesis in bovine mammary gland. This implies that occupation of the respective receptors by either chimeric GH or hGH leads to identical postreceptoral effects. The chimeric GH was also capable of down-regulating the lactogenic receptors in Nb2 lymphoma cells and was recognized by three anti-hGH monoclonal antibodies. These and previously published results indicate that the N-terminal part of hGH is essential for the high affinity binding to lactogenic receptors and subsequent biological effect. Removal or replacement by a corresponding part of bovine GH converts the hormone, respectively to weak antagonist or agonists. Analysis of our data, based on hydropathy index leads us to suggest that the high affinity binding site of the hGH towards lactogenic receptors is mainly confined to amino acids nos. 8-18.
AB - A chimeric bovine GH (amino acids Met-Asp-Gln->1-23) and human GH (hGH) (amino acids 24-191) plasmid was constructed and expressed in Escherichia coii. The purified protein (chimeric GH) exhibited a 2-3 order of magnitude lower affinity toward lactogenic receptors in Nb2 lymphoma cells, microsomal fractions from bovine mammary gland and male rat liver. The affinity towards somatogenic receptors in IM-9 human lymphocytes and male rat liver was decreased to a much lesser degree.This diminished affinity towards lactogenic receptors was accompanied by a parallel decrease in the ability of the chimeric GH to stimulate proliferation of Nb2-11C lymphoma cells and the lipogenesis in bovine mammary gland. This implies that occupation of the respective receptors by either chimeric GH or hGH leads to identical postreceptoral effects. The chimeric GH was also capable of down-regulating the lactogenic receptors in Nb2 lymphoma cells and was recognized by three anti-hGH monoclonal antibodies. These and previously published results indicate that the N-terminal part of hGH is essential for the high affinity binding to lactogenic receptors and subsequent biological effect. Removal or replacement by a corresponding part of bovine GH converts the hormone, respectively to weak antagonist or agonists. Analysis of our data, based on hydropathy index leads us to suggest that the high affinity binding site of the hGH towards lactogenic receptors is mainly confined to amino acids nos. 8-18.
UR - http://www.scopus.com/inward/record.url?scp=0024411387&partnerID=8YFLogxK
U2 - 10.1210/mend-3-6-923
DO - 10.1210/mend-3-6-923
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C2 - 2739655
AN - SCOPUS:0024411387
SN - 0888-8809
VL - 3
SP - 923
EP - 930
JO - Molecular Endocrinology
JF - Molecular Endocrinology
IS - 6
ER -