RNA localization and translational regulation are used during Drosophila oogenesis and early embryogenesis to restrict distribution of gene products required for the establishment of the embryonic axes. The establishment of oocyte polarity can be traced back to the germ line stem cell. At each division the stem cell produces another stem cell and a cystoblast cell that undergoes four rounds of division. Fifteen cells become polyploid nurse cells, one the oocyte, egalitarian (egl) and BicaudalD (BicD) have the same phenotype: no oocyte is determined, all 16 sisters become nurse cells. Egl and BicD form a protein complex that is required to maintain a polarized microtubule network and to promote RNA transport from the nurse cells into the oocyte. The first indicator of oocyte polarity is localization of bicoid and oskar RNA to the anterior and posterior poles. The site of oskar RNA and protein localization within the oocyte determines where in the embryo nanos (nos) RNA becomes localized and translated. The Sos protein gradient as well as the uniformly distributed Pumilio (pum) are necessary to inhibit translation of the transcriptional repressor hunchback (hb), and thereby permit expression of embryonic genes required for abdomen formation. Pure contains a novel, conserved RNA binding domain that binds specifically to a small region in the hb 3UTR that confers hb regulation. (Supported grant HD27549 from the NIH).
|Original language||English (US)|
|State||Published - Dec 1 1997|
ASJC Scopus subject areas
- Molecular Biology