Lin Ming-Der, Jiao Xinfu, Grima Dominic, Newbury Sarah F, Kiledjian Megerditch, Chou Tze-Bin
Institute of Molecular and Cellular Biology, College of Life Science, National Taiwan University, Taipei, Taiwan.
Dev Biol. 2008 Oct 15;322(2):276-88. doi: 10.1016/j.ydbio.2008.07.033. Epub 2008 Aug 5.
Processing bodies (P-bodies) have emerged as important subcellular structures that are involved in mRNA metabolism. To date, a detailed description of P-bodies in Drosophila oogenesis is lacking. To this end, we first demonstrate that Drosophila decapping protein 2 (dDcp2) contains intrinsic decapping activity and its enzymatic activity was not detectably enhanced by Drosophila decapping protein 1 (dDcp1). dDcp1-containing bodies in the nurse cell cytoplasm can associate with the 5' to 3' exoribonuclease, Pacman in addition to dDcp2 and Me31B. The size and number of dDcp1 bodies are dynamic and dramatically increased in dDcp2 and pacman mutant backgrounds supporting the conclusion that dDcp1 bodies in nurse cell cytoplasm are Drosophila P-bodies. In stage 2-6 oocytes, dDcp1 bodies appear to be distinct from previously characterized P-bodies since they are insensitive to cycloheximide and RNase A treatments. Curiously, dDcp2 and Pacman do not colocalize with dDcp1 at the posterior end of the oocyte in stage 9-10 oocytes. This suggests that dDcp1 bodies are in a developmentally distinct state separate from the 5' end mRNA degradation enzymes at later stages in the oocyte. Interestingly, re-formation of maternally expressed dDcp1 with dDcp2 and Pacman was observed in early embryogenesis. With respect to developmental switching, the maternal dDcp1 is proposed to serve as a marker for the re-formation of P-bodies in early embryos. This also suggests that a regulated conversion occurs between maternal RNA granules and P-bodies from oogenesis to embryogenesis.
加工小体(P小体)已成为参与mRNA代谢的重要亚细胞结构。迄今为止,缺乏对果蝇卵子发生过程中P小体的详细描述。为此,我们首先证明果蝇去帽蛋白2(dDcp2)具有内在的去帽活性,并且果蝇去帽蛋白1(dDcp1)未显著增强其酶活性。除dDcp2和Me31B外,营养细胞胞质中含dDcp1的小体还可与5'至3'外切核糖核酸酶Pacman结合。dDcp1小体的大小和数量是动态的,并且在dDcp2和pacman突变背景下显著增加,这支持了营养细胞胞质中的dDcp1小体是果蝇P小体的结论。在2-6期卵母细胞中,dDcp1小体似乎与先前表征的P小体不同,因为它们对环己酰亚胺和核糖核酸酶A处理不敏感。奇怪的是,在9-10期卵母细胞中,dDcp2和Pacman在卵母细胞后端不与dDcp1共定位。这表明dDcp1小体在发育上处于与卵母细胞后期5'端mRNA降解酶不同的状态。有趣的是,在早期胚胎发生过程中观察到母体表达的dDcp1与dDcp2和Pacman重新形成。关于发育转换,母体dDcp1被认为是早期胚胎中P小体重新形成的标志物。这也表明从卵子发生到胚胎发生过程中,母体RNA颗粒和P小体之间发生了调节性转换。