CONTROL MECHANISMS AND DIFFERENTIATION

酵母中从有丝分裂到减数分裂和孢子形成的转变 酿酒酵母，其通常由营养物质引发， 剥夺，可以特异性地由部分鸟嘌呤或甲硫氨酸引发 剥夺 所有这些条件导致细胞内GTP的减少 而其他核苷酸的浓度保持不变，增加 或减少，这取决于用于启动的特定条件 减数分裂 其他代谢产物参与孢子形成诱导， 被排除在外;特别是，可以找到的条件下， 细胞GTP降低，而S-腺苷甲硫氨酸或环AMP 并不改变，但细胞能很好地进行减数分裂和孢子形成。 核和核基质蛋白，其中受到二维 电泳和某些蛋白质被发现在减数分裂过程中发生变化。 一种核基质蛋白的基因是从小鼠和 酵母DNA文库 谷氨酰胺合成酶的基因与 从这两个图书馆。 在枯草芽孢杆菌中， 抑制浓度的乙烯利引起了连续产孢 变种人 这种效应取决于乙醇转化为 S-腺苷硫醚，并推测涉及抑制甲基化 反应

The switch from mitosis to meiosis and sporulation in the yeast Saccharomyces cerevisiae, which is normally initiated by nutritional deprivation, can be specifically initiated by partial guanine or methionine deprivation. All these conditions led to the decrease of intracellular GTP whereas the concentrations of other nucleotides remain constant, increase or decrease, depending on the particular condition used to initiate meiosis. Involvement of other metabolites in sporulation induction has been ruled out; in particular, conditions can be found under which the cellular GTP decreases while that of S-adenosylmethionine or cyclic AMP does not change and yet the cells go through meiosis and sporulate well. Nuclear and nuclear matrix proteins where subjected to two-dimensional electrophoresis and certain proteins were found to change during meiosis. The gene for one nuclear matrix proteins was cloned from both a mouse and a yeast DNA library. The gene for glutamine synthetase was similarly obtained from these two libraries. In Bacillus subtilis partially inhibitory concentrations of ethionine caused continual sporulation in eth mutants. This effect depends on the conversion of ethionine to S-adenosylethionine and presumably involves the inhibition of a methylation reaction.