PREMEIOTIC DNA-SYNTHESIS IN FISSION YEAST
PREMEIOTIC DNA-SYNTHESIS IN FISSION YEAST
复制标题
DOI：
10.1016/0014-4827(74)90626-0
复制
发表时间：
1974-01-01
影响因子：
3.7
通讯作者：
EGELMITA.M
中科院分区：
文献类型：
--
作者：
EGEL, R;EGELMITA.M
比较了产孢菌和非产孢菌，特别是接合或减数分裂缺陷的几个突变株在产孢子条件下的DNA合成。通过转移到无氮培养基来诱导减数分裂和产孢量。由于所有菌株都观察到了同步的有丝分裂，作为对这种转变的第一反应，在细胞周期的G1期，每个细胞的DNA含量从G2的复制状态减少到非复制状态。异源野生型菌株(h+h+或h−h−)单独培养时，细胞在G1期积累。在这些菌株的混合培养中，在合子形成开始后观察到一段时间的DNA合成增强。突变体FUS1没有这个合成期，只积累了前合子。因此，我们得出结论，在合子减数分裂中，减数分裂前DNA的合成仅限于接合完成后的合子。在二倍体产孢型野生型菌株(h+h−)中，可以在没有事先接合的情况下进行氮合减数分裂，减数分裂前的DNA合成发生在转移到产孢剂后的2 1 2~5 h之间。在减数分裂缺陷突变体mei1或mei3的二倍体细胞中没有观察到明显的减数分裂前DNA合成，而突变体mei4的减数分裂前DNA合成正常进行，这一过程在减数分裂后被阻止，与其他两个突变体相反。
Sporulating and various non-sporulating strains of S. pombe, especially several mutants deficient in conjugation or meiosis, were compared with respect to DNA synthesis under sporulation conditions. Meiosis and sporulation were induced by a transfer to nitrogen-free medium. As synchronized mitotic division was observed in all the strains as a first response to the shift, reducing the DNA amount per cell from the replicated state in G2 to the unreplicated state in the G1 phase of the cell cycle. Cells of the heterothallic wild-type strains (h+ h+ or h− h−) accumulated in G1 with respect to DNA synthesis when they were incubated separately. In a mixed culture of these strains a period of enhanced DNA synthesis was observed after the start of zygote formation. This period of synthesis was absent in mutant fus1, where only prezygotes accumulated. Hence we conclude that in zygotic meiosis the premeiotic DNA synthesis is confined to zygotes after conjugation has been completed. In the diploid sporulating wild-type strain (h+ h−), capable of azygotic meiosis without prior conjugation, premeiotic DNA synthesis occurred between 2 1 2 and 5 h after the shift to the sporulation medium. There was no significant premeiotic DNA synthesis observed in diploid cells of the meiosis-deficient mutants mei1 or mei3, whereas premeiotic DNA synthesis proceeded normally in mutant mei4, which is blocked at a stage after commitment to meiosis in opposition to both the other mutants.