Effects of thyrotropin on thyroid chromatin. Enhanced sensitivity to micrococcal nuclease and increased nuclear protein phosphorylation.
Thyroid slices were incubated with or without TSH for 2 or 5 h. Nuclei were then prepared, subjected to mild digestion with micrococcal nuclease, and centrifuged at 1200 X g. The amount of DNA in 1200 X g supernatants was increased by TSH at 5 h, but not at 2 h. In parallel studies, thyroid slices were incubated with 32Pi and labeling of acid-soluble nuclear proteins was examined. TSH-dependent increases in labeling of histones H1 and H3, and of the high mobility group protein HMG 14, were observed at 2 h; however, there were no apparent changes in TSH-dependent labeling between 2 and 5 h, in nuclease-sensitive or in bulk chromatin. These results suggest that the observed TSH-dependent changes in the micrococcal nuclease-sensitivity of thyroid nuclear chromatin were not induced directly by changes in the phosphorylation of the histones or HMG 14.
D000818:Animals; D002417:Cattle; D002843:Chromatin / Q000187:drug effects*; D004247:DNA / Q000378:metabolism; D008836:Micrococcal Nuclease / Q000378:metabolism*; D009698:Nucleoproteins / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D013961:Thyroid Gland / Q000187:drug effects / Q000648:ultrastructure*; D013972:Thyrotropin / Q000494:pharmacology*
D002843:Chromatin; D009698:Nucleoproteins; D010750:Phosphoproteins; D013972:Thyrotropin; D004247:DNA; D008836:Micrococcal Nuclease