Discrete sequence elements control posterior pole accumulation and translational repression of maternal cyclin B RNA in Drosophila.

Abstract

The concentration of cyclin B transcripts at the posterior pole of the Drosophila oocyte occurs at a late stage of oogenesis and is dependent on the sequence in the 3′ untranslated part of the RNA. These transcripts become incorporated into the pole cells of the developing embryo and persist through a subsequent period of embryogenesis in which these cells are not dividing. We show that RNA injected into the posterior cytoplasm of syncytial embryos accumulates in the pole cells if it contains sequences present in the 3′ untranslated region of maternal cyclin B transcripts. The injected RNA is not translated until a point prior to the resumption of mitosis by these cells, once they have become incorporated into the gonads. Zygotic transcription directed from the cyclin B promoter does not begin in the pole cells until the first instar larva has hatched. Deletion of a small sequence element from the 3′ untranslated region of an epitope tagged cyclin B RNA does not affect its posterior accumulation but results in its premature translation.

Predicting in vivo binding sites of RNA-binding proteins using mRNA secondary structure

“…To date, all known Puf proteins bind their targets through this domain and subsequently regulate the stability and/or translation of these targets (Wharton et al 1998;Olivas and Parker 2000;Goldstrohm et al 2006;Hook et al 2007). Structural (Wang et al 2002;Miller et al 2008;Zhu et al 2009), small-scale (Dalby and Glover 1993;Jackson et al 2004), and large-scale (Gerber et al 2004(Gerber et al , 2006 studies are consistent with a conserved single-stranded consensus binding sequence, UGUAHAUA, for Pumilio and Puf3p (H indicates that A, C, or U is permitted).…”

Sequences responsible for intracellular localization of beta-actin messenger RNA also affect cell phenotype.

“…For instance, repression of translation of two morphogens, bicoid and hunchback, requires nanos (nos) protein, occurs through a small YUTR sequence called nos-responsive element (NRE), which may act to destabilize NRE containing RNAs 0?¢harton and Struhl, 1991). The NRE appears to be necessary for the translational control but not localization of cyclin B mRNA at the posterior pole (Dalby and Glover, 1993). A distinction between localization determinants and NREs also remains unclear for the C. elegans glp-1 gene.…”

“…Other Drosophila 3TITR localization signals include an anterior localization signal in the zygotic K10 gene restricted to a ~l.4-kb 3' segment (Cheung et al, 1992). Posterior localization signals have been found within the ,~l.7-kb segment of the maternal mRNA coding for nanos (Gavis and Lehmann, 1992), the '~l.l-kb 3%rl'R of oskar (Kim-Ha et al, 1993), and two closely apposed segments of 94 and 87 nt within the cyclin B (Dalby and Glover, 1993). In blastoderm embryos, apical localization signals have been identified on zygotic pair-rule transcripts with the shortest occurring within the last 124 nt of the even-skipped gene (Davis and Ish-Horowicz, 1992).…”

A Minimal WLE2 Element is Not Sufficient to Direct Apical Localization in the Absence of RNAs Containing the Full Length Wingless 3'UTR

“…The 3'UTR of other localized RNAs have been shown to contain multiple regions responsible for different aspects of localization such as translational suppression, different patterns of localization during stages of development or acting as flexible linkers. 52,[57][58][59][60][61][62] Notably, RNAs expressed from genes such as bcd 63,64 and osk 65 have additional regions within the 3'UTR that have been implicated in the formation of RNA-RNA homodimers that seem to be needed for localization of these transcripts.…”