Department of Biochemistry and Howard Hughes Medical Institute, University of Wisconsin, Madison, WI 53706, USA.
Proc Natl Acad Sci U S A. 2010 Oct 5;107(40):17445-50. doi: 10.1073/pnas.1012611107. Epub 2010 Sep 20.
Regulated polyadenylation is a broadly conserved mechanism that controls key events during oogenesis. Pivotal to that mechanism is GLD-2, a catalytic subunit of cytoplasmic poly(A) polymerase (PAP). Caenorhabditis elegans GLD-2 forms an active PAP with multiple RNA-binding partners to regulate diverse aspects of germline and early embryonic development. One GLD-2 partner, RNP-8, was previously shown to influence oocyte fate specification. Here we use a genomic approach to identify transcripts selectively associated with both GLD-2 and RNP-8. Among the 335 GLD-2/RNP-8 potential targets, most were annotated as germline mRNAs and many as maternal mRNAs. These targets include gld-2 and rnp-8 themselves, suggesting autoregulation. Removal of either GLD-2 or RNP-8 resulted in shortened poly(A) tails and lowered abundance of four target mRNAs (oma-2, egg-1, pup-2, and tra-2); GLD-2 depletion also lowered the abundance of most GLD-2/RNP-8 putative target mRNAs when assayed on microarrays. Therefore, GLD-2/RNP-8 appears to polyadenylate and stabilize its target mRNAs. We also provide evidence that rnp-8 influences oocyte development; rnp-8 null mutants have more germ cell corpses and fewer oocytes than normal. Furthermore, RNP-8 appears to work synergistically with another GLD-2-binding partner, GLD-3, to ensure normal oogenesis. We propose that the GLD-2/RNP-8 enzyme is a broad-spectrum regulator of the oogenesis program that acts within an RNA regulatory network to specify and produce fully functional oocytes.
调控的多聚腺苷酸化是一种广泛保守的机制,它控制着卵子发生过程中的关键事件。这一机制的关键是 GLD-2,细胞质多聚(A)聚合酶(PAP)的催化亚基。秀丽隐杆线虫 GLD-2 与多个 RNA 结合伙伴形成活性 PAP,调节生殖系和早期胚胎发育的多个方面。GLD-2 的一个伙伴 RNP-8 先前被证明影响卵母细胞命运的特化。在这里,我们使用基因组方法来鉴定与 GLD-2 和 RNP-8 都有选择性关联的转录本。在 335 个 GLD-2/RNP-8 潜在靶标中,大多数被注释为生殖系 mRNA,许多为母本 mRNA。这些靶标包括 gld-2 和 rnp-8 本身,表明存在自身调控。去除 GLD-2 或 RNP-8 都会导致 poly(A)尾巴缩短,以及四个靶标 mRNA(oma-2、egg-1、pup-2 和 tra-2)的丰度降低;当在微阵列上进行检测时,GLD-2 耗竭也降低了大多数 GLD-2/RNP-8 假定靶标 mRNA 的丰度。因此,GLD-2/RNP-8 似乎可以多聚腺苷酸化并稳定其靶标 mRNA。我们还提供了证据表明 rnp-8 影响卵母细胞的发育;rnp-8 缺失突变体比正常情况下有更多的生殖细胞尸体和更少的卵母细胞。此外,RNP-8 似乎与另一个与 GLD-2 结合的伙伴 GLD-3 协同作用,以确保正常的卵子发生。我们提出,GLD-2/RNP-8 酶是卵子发生程序的广谱调节剂,它在 RNA 调控网络内发挥作用,以指定和产生具有完全功能的卵母细胞。