Dispensability of nanos mRNA localization for abdominal patterning but not for germ cell development

Abstract

The development of a functional germline is essential for species propagation. The nanos (nos) gene plays an evolutionarily conserved role in germline development and is also essential for abdominal patterning in Drosophila. A small fraction of nos mRNA is localized to the germ plasm at the posterior pole of the Drosophila embryo, where it becomes incorporated into the germ cells. Germ plasm associated nos mRNA is translated to produce a gradient of Nos protein that patterns the abdomen, whereas the remaining unlocalized RNA is translationally repressed to allow anterior development. Using transgenes that compromise nos mRNA localization and translational regulation, we show that wild-type body patterning can ensue without nos mRNA localization provided that nos translation is properly modulated. In contrast, localization of nos to the germ plasm, but not translational regulation, is essential for nos function in the developing germ cells. We propose that an imperative for nos localization in producing a functional germline has preserved an inefficient localization mechanism.

Localization, anchoring and translational control ofoskar,gurken,bicoidandnanosmRNA during Drosophila oogenesis

“…117 nos mRNA localization and translation are elaborately regulated in the embryo, with translational regulation being predominantly involved in abdominal pattern formation while the posterior accumulation of nos mRNA is essential for its role in germ cell development. 118 nos mRNA accumulates in an asymmetric pattern during most stages of oogenesis (reviewed in ref. 17).…”

Xenopusgermlinenanos1is translationally repressed by a novel structure-based mechanism

“…Alternatively, any nanos1 RNA outside the germ plasm would have to be efficiently degraded, a mechanism described for nanos in Drosophila and zebrafish (Bashirullah et al, 1999;Mishima et al, 2006). Both Drosophila and zebrafish have inefficient modes of nanos RNA localization, necessitating a post-transcriptional control mechanism (Gavis et al, 2008;Giraldez et al, 2006). In zebrafish, maternal mRNAs are degraded by zygotic miR-430 during early embryogenesis.…”

TheDrosophilahnRNP M homolog Rumpelstiltskin regulatesnanosmRNA localization

“…The obligate linkage of nos mRNA localization and translation prevents synthesis of Nos in the anterior of the embryo, where it is deleterious to head and thorax development (Gavis and Lehmann, 1992;Gavis and Lehmann, 1994;Wharton and Struhl, 1989). Recently, posterior localization of nos has also been shown to be essential for nos function in germ cell development (Gavis et al, 2008).…”