title: Chromatin structure of the rat somatotropin gene locus and physical linkage of the rat somatotropin gene and skeletal-muscle sodium-channel gene.
abstract: Cosmid clones from -32 kb to +74 kb region of the rat somatotropin gene locus were isolated for examination of the chromatin structure in the region from -39 kb to +47 kb by DNase I-sensitivity analysis using rat pituitary-derived GC (somatotropin+, prolactin-), and 235 (somatotropin-, prolactin+) cells, and liver-derived BRL (somatotropin-, prolactin-) cells. DNase I-hypersensitive sites (DHS) specific for somatotropin-producing cells were previously shown to be located exclusively in the -2 kb to +9 kb region [Aizawa, A., Yoneyama, T., Kazahari, K. & Ono, M. (1995) Nucleic Acids Res. 23, 2236-2244]. No other DHS having this specificity was found in the region examined in this study. Except for these and two other DHS located in a cluster in this region, no DHS could be found from -23 kb to +22 kb. DHS having no or less cell-type specificity were scattered about in the -39 kb to -23 kb and +22 kb to +47 kb regions. The polyadenylation site of the human skeletal-muscle Na-channel alpha-subunit gene has been shown present 22 kb upstream from the somatotropin gene [Bennani-Baiti, I. M., Jones, B. K., Liebhaber, S. A. & Cooke, N. E. (1995) Genomics 29, 647-652]. Polyadenylation site of the rat skeletal-muscle Na-channel gene was shown in this study to be at -15.7 kb. The skeletal-muscle Na-channel gene was specifically expressed in skeletal-muscle cells but not in somatotropin-producing cells, and thus the boundary region that ensures the cell-type-specific expression of each gene would appear to be situated between two genes. The region prerequisite for cell-type-specific expression of the rat somatotropin gene was estimated based on the present findings.
authors.affiliation: Department of Molecular Biology, School of Medicine, Kitasato University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kazahari
authors.forename: E
authors.initials: E
authors.lastname: Sano
authors.forename: N
authors.initials: N
authors.lastname: Matsuura
authors.forename: M
authors.initials: M
authors.lastname: Ono
mesh_terms: D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002843:Chromatin / Q000737:chemistry* / Q000235:genetics*; D003001:Cloning, Molecular; D003360:Cosmids; D018076:DNA, Complementary / Q000235:genetics; D003850:Deoxyribonuclease I; D015870:Gene Expression; D008040:Genetic Linkage; D013006:Growth Hormone / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000378:metabolism; D010902:Pituitary Gland / Q000378:metabolism; D051381:Rats; D015183:Restriction Mapping; D015222:Sodium Channels / Q000235:genetics*
chemical_list: D002843:Chromatin; D018076:DNA, Complementary; D015222:Sodium Channels; D013006:Growth Hormone; D003850:Deoxyribonuclease I