Felgenhauer P, Sedman J, Shostak N, Timofeeva M, Lind A, Bayev A
W. Engelhardt Institute of Molecular Biology, USSR Academy of Sciences, Moscow.
Gene. 1990 Jun 15;90(2):243-8. doi: 10.1016/0378-1119(90)90186-u.
Deletion mutants of loach oocyte 5S rRNA genes were injected and transcribed in vivo in the nuclei of loach (Misgurnus fossilis) and Xenopus laevis. A control region was found in the 5'-flanking sequence, the elimination of which greatly decreases in vivo transcription of 5S rRNA genes. This cis-acting element is located in the region between nt-18 and the transcription start point. We propose that the oocyte nucleus contains (a) specific transcriptional factor(s), NTFO, which interacts with the cis-acting element we described. We also propose that NTFO is inactivated in maturing oocytes when nucleoplasm interacts with oocyte cytoplasm after germinal vesicle breakdown. The residual activity of this factor(s) may be responsible for low-level synthesis of oocyte 5S rRNA at the beginning of embryogenesis. We consider the disappearance of NTFO during gastrulation to be responsible for the total inactivation of oocyte 5S rRNA genes in embryonic and somatic tissue.
将泥鳅卵母细胞5S rRNA基因的缺失突变体注射到泥鳅（Misgurnus fossilis）和非洲爪蟾（Xenopus laevis）的细胞核中进行体内转录。在5'侧翼序列中发现了一个控制区，去除该区会大大降低5S rRNA基因的体内转录。这个顺式作用元件位于nt - 18与转录起始点之间的区域。我们提出，卵母细胞核含有一种或多种与我们所描述的顺式作用元件相互作用的特异性转录因子NTFO。我们还提出，在生发泡破裂后核质与卵母细胞胞质相互作用时，NTFO在成熟卵母细胞中失活。该因子的残余活性可能是胚胎发生开始时卵母细胞5S rRNA低水平合成的原因。我们认为原肠胚形成期间NTFO的消失是胚胎和体细胞组织中卵母细胞5S rRNA基因完全失活的原因。
