Storch T G
Department of Pediatrics, Tulane University School of Medicine, New Orleans, LA 70112.
Biochim Biophys Acta. 1990 Nov 12;1055(2):126-9. doi: 10.1016/0167-4889(90)90112-q.
This study reports that changing the oxygen concentration within a physiologic range has a striking effect on myogenesis induced by the cytidine analog 5-azacytidine. Reducing oxygen from 20% to 2.5% increases 7-fold the number of myocytes that appear in cultures of C3H/10T1/2 mouse embryo cells 10 days after they receive a 24-h exposure to 5-azacytidine. Reducing oxygen does not alter the extent to which a 24-h exposure to 5-azacytidine inhibits cytosine methylation in newly synthesized DNA. Instead, the oxygen-sensitive step in myogenesis occurs after 5-azacytidine is removed from the culture medium. Reducing oxygen increases the rate of logarithmic growth in C3H/10T1/2 cultures after 5-azacytidine exposure, suggesting that survival and proliferation of myocyte stem cells (morphologically indistinguishable from uncommitted C3H/10T1/2 cells) may be the oxygen-sensitive steps in myogenesis.
本研究报告称，在生理范围内改变氧气浓度对胞苷类似物5-氮杂胞苷诱导的成肌作用有显著影响。将氧气浓度从20%降至2.5%，可使C3H/10T1/2小鼠胚胎细胞在接受24小时5-氮杂胞苷处理后10天出现的肌细胞数量增加7倍。降低氧气浓度并不会改变24小时暴露于5-氮杂胞苷对新合成DNA中胞嘧啶甲基化的抑制程度。相反，成肌过程中对氧气敏感的步骤发生在5-氮杂胞苷从培养基中去除之后。降低氧气浓度会增加5-氮杂胞苷处理后C3H/10T1/2培养物中的对数生长速率，这表明肌细胞干细胞（在形态上与未定向的C3H/10T1/2细胞无法区分）的存活和增殖可能是成肌过程中对氧气敏感的步骤。
