Effect of site directed mutagenesis in the CMGCC region of the alpha-subunit on immunoreactive human thyrotropin.
The cDNA of the common alpha-subunit of human glycoprotein hormone was mutated by site directed mutagenesis in the CMGCC region composed of cysteine-methionine-glycine-cysteine-cysteine (position 28-32). The cDNA of wild-type human thyrotropin (hTSH) beta-subunit and that of wild-type or mutant common alpha-subunits were co-transfected into COS-I cells. The concentration of hTSH determined by two immunoradiometric assay systems was detectable in culture media of COS-I cells transfected with wild-type (CMGCC) and a mutant (CRGCC) alpha-subunits but not four other mutants (YMGCC) (CMRCC) (CMACC) (CMDCC). The present data with the other studies on wild-type or mutant glycoprotein hormones support our hypothesis that an amino acid motif of "C-X-G-X-C" in the common alpha-(CMGCC in human) and beta-(CAGYC in human) subunits play an important role in biosynthesis of glycoprotein hormones in all species.
Miyai
K
K
Koshien University College of Nutrition, Japan.
Kumazawa
I
I
Saji
F
F
Azuma
C
C
Koyama
M
M
Kimura
T
T
Narizuka
Y
Y
Kusunoki
M
M
Murata
Y
Y
D019943:Amino Acid Substitution; D000818:Animals; D019556:COS Cells; D018274:Electroporation; D015292:Glycoprotein Hormones, alpha Subunit / Q000737:chemistry / Q000235:genetics*; D006801:Humans; D007118:Immunoassay; D016297:Mutagenesis, Site-Directed; D011863:Radioimmunoassay; D011933:Reagent Kits, Diagnostic; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D013972:Thyrotropin / Q000032:analysis / Q000737:chemistry / Q000235:genetics*; D014162:Transfection
D015292:Glycoprotein Hormones, alpha Subunit; D011933:Reagent Kits, Diagnostic; D013972:Thyrotropin