タイトル無し
スポンサーリンク
概要
- 論文の詳細を見る
The activities of erythroid cells to synthesize DNA, RNA, and protein are sequentially lost as the cells mature. Since erythrocytes of lower vertebrates, in contrast to those of mammalians, retain nuclei even when they have matured, the nucleated erythrocyte is a convenient probe for studying the relationship between the structure and the function of chromatin. In avian erythrocytes, it has been reported that histone H 5 specific for the nucleated erythrocyte appears and the repeat length of nucleosome elongates during maturation. From the comparative biochemical point of view, I have studied histone composition and nucleosome structure of the chromatin from the nucleated erythrocytes of bullfrog, <I>Rana catesbeiana</I>. It has been found that the nucleated erythrocytes of amphibian makedly differs in the chromatin structure from those of avian.<BR>The chromatin of frog erythrocyte consists of five major histories (H1A, H2A, H2B, H3, and H 4) and three minor histories (H1B, R 1, and R 2). The five major histories are almost identical with those of hen erythrocytes. However, it is characteristic of the chromatin of frog erythrocytes that it lacks histone H 5, which is an additional major histone of hen erythrocytes and has been considered specific for the nucleated erythrocyte so far, and that it has the three minor histones, which are not found in hen erythrocytes. H1B is a very lysine-rich histone and has essentially the same amino acid composition as that of H 1. K, a subfraction of lysine-rich histories extracted from bovine liver. R 1, differing in the amino acid composition from any chromosomal proteins so far reported, is rich in lysine and alanine and has alanine residue as N-terminus. R 2 has both acidic and basic amino acids in an equal amount and methionine residue as a N-terminus. On the basis of the amino acid composition and the position migrated in two dimentional gel electrophoresis, R 2 is identified as A 24 protein, a molecule composed of H2A and ubiquitin covalently attached through an isopeptide linkage. Histone H 1. K and A24 protein are known to be specific for a non-dividing cell and to appear when template activity decreases, respectively. Therefore, in the frog erythrocyte lacking H 5, H 1. K-like histone and A 24 protein may play a central role in genetic inactivation during the erythrocyte maturation.<BR>The nucleosome repeat lengths are determined to be 196 and 195 for the erythrocyte and liver of frog, and 208 and 197 for those of hen, respectively. It appears that there is no difference in the length between transcriptionally inactive erythrocyte and active liver of the frog, while the length of hen erythrocyte is longer by about 10 base pairs than that of hen liver. All the results described here suggest that the mechanism, by which the maturation of the amphibian erythrocyte is regulated, is different from that of the avian erythrocyte.
- 日本医科大学医学会の論文
日本医科大学医学会 | 論文
- わが国における腸チフスの疫学的考察--1973年〜1976年届出菌検出例を中心として
- 臨床および実験報告 二絨毛膜双胎妊娠における高年初産の検討
- 救急災害医学の確立と展望[含 略歴 研究業績] (定年退職教授記念講演会講演要旨)
- 臨床のために 関節リウマチの診断と治療
- TNFファミリーの制御による関節リウマチ治療の可能性 (特集 第15回公開「シンポジウム」(アレルギー・膠原病に対する新たな展開))