Effects of thyrotropin on the phosphorylation of histones and nonhistone phosphoproteins in micrococcal nuclease-sensitive and resistant thyroid chromatin
Actively transcribed regions of chromatin are more susceptible than bulk chromatin to digestion by nucleases, and useful information about the composition and structure of active chromatin may be obtained by studying the chromatin fragments released from nuclei by limited nuclease digestion. In the present study, we have used micrococcal nuclease to investigate the effects of TSH on protein phosphorylation in nuclease-sensitive fractions of calf thyroid chromatin. Batches of calf thyroid slices were incubated for 2 h with /sup 32/Pi, with or without 50 mU/ml TSH. Nuclei were then prepared and the distribution of /sup 32/P-labeled histones, high mobility group (HMG) proteins, and other acid-soluble phosphoproteins between micrococcal nuclease-sensitive and resistant fractions of chromatin was examined. TSH increased the amount of /sup 32/P incorporated into HMG 14 and the histones H1 and H3. Hormone-dependent increases in the /sup 32/P-labeling of H1 and H3 were not selectively associated with micrococcal nuclease-sensitive chromatin. In contrast, (/sup 32/P) HMG-14 was preferentially solubilized from nuclei by micrococcal nuclease. This lends support to the view that TSH-induced effects on the structure and function of transcriptionally active chromatin may be mediated in part by phosphorylation of HMG 14.
- Research Organization:
- State University of New York, Department of Medicine, Buffalo General Hospital
- OSTI ID:
- 5856372
- Journal Information:
- Endocrinology; (United States), Vol. 112:5
- Country of Publication:
- United States
- Language:
- English
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HISTONES
PHOSPHORYLATION
PHOSPHORUS 32
TRACER TECHNIQUES
PROTEINS
TSH
BIOLOGICAL FUNCTIONS
CHROMATIN
LABELLED COMPOUNDS
NUCLEASES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CHEMICAL REACTIONS
DAYS LIVING RADIOISOTOPES
ENZYMES
ESTERASES
FUNCTIONS
HORMONES
HYDROLASES
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PEPTIDE HORMONES
PHOSPHODIESTERASES
PHOSPHORUS ISOTOPES
PITUITARY HORMONES
RADIOISOTOPES
550201* - Biochemistry- Tracer Techniques