Active domains in wild-type and mutant glucocorticoid receptors.
[3H]Triamcinolone acetonide was used to tag covalently specific glucocorticoid receptors by photoaffinity labelling at lambda greater than or equal to 320 nm. Receptors of wild-type mouse lymphoma cells and two glucocorticoid resistant mutants of "nuclear transfer deficient" (nt-) and "increased nuclear transfer" (nti) phenotypes, respectively, were used. Wild-type and nt- receptors yielded radiolabelled polypeptide bands of mol. wt. 98 000 as revealed by gel electrophoresis under denaturing conditions and fluorography. In contrast, the nti receptor had a mol. wt. of 42 000. Partial proteolysis of the wild-type receptor with alpha-chymotrypsin resulted in a fragment of mol. wt. 39 000 which still contained the steroid binding site but had increased affinity for DNA indistinguishable from that of the nti receptor. Chymotrypsin thus removed a domain from the wild-type receptor polypeptide which is involved in modulating DNA binding. The same domain is missing from the nti receptor.
D000818:Animals; D002460:Cell Line; D002918:Chymotrypsin / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D051379:Mice; D008970:Molecular Weight; D009154:Mutation; D010777:Photochemistry; D011965:Receptors, Glucocorticoid / Q000235:genetics* / Q000378:metabolism; D011987:Receptors, Steroid / Q000235:genetics*; D014222:Triamcinolone Acetonide / Q000378:metabolism
D011965:Receptors, Glucocorticoid; D011987:Receptors, Steroid; D002918:Chymotrypsin; D014222:Triamcinolone Acetonide