A genetic pathway for regulation of tra-2 translation

Development ◽  
1997 ◽  
Vol 124 (3) ◽  
pp. 749-758 ◽  
Author(s):  
E.B. Goodwin ◽  
K. Hofstra ◽  
C.A. Hurney ◽  
S. Mango ◽  
J. Kimble

In Caenorhabditis elegans, the tra-2 sex-determining gene is regulated at the translational level by two 28 nt direct repeat elements (DREs) located in its 3′ untranslated region (3′UTR). DRF is a factor that binds the DREs and may be a trans-acting translational regulator of tra-2. Here we identify two genes that are required for the normal pattern of translational control. A newly identified gene, called laf-1, is required for translational repression by the tra-2 3′UTR. In addition, the sex-determining gene, tra-3, appears to promote female development by freeing tra-2 from laf-1 repression. Finally, we show that DRF activity correlates with translational repression of tra-2 during development and that tra-3 regulates DRF activity. We suggest that tra-3 may promote female development by releasing tra-2 from translation repression by laf-1 and that translational control is important for proper sex determination--both in the early embryo and during postembryonic development.

Development ◽  
1999 ◽  
Vol 126 (4) ◽  
pp. 659-669 ◽  
Author(s):  
S.E. Bergsten ◽  
E.R. Gavis

Patterning of the anterior-posterior body axis during Drosophila development depends on the restriction of Nanos protein to the posterior of the early embryo. Synthesis of Nanos occurs only when maternally provided nanos RNA is localized to the posterior pole by a large, cis-acting signal in the nanos 3′ untranslated region (3′UTR); translation of unlocalized nanos RNA is repressed by a 90 nucleotide Translational Control Element (TCE), also in the 3′UTR. We now show quantitatively that the majority of nanos RNA in the embryo is not localized to the posterior pole but is distributed throughout the cytoplasm, indicating that translational repression is the primary mechanism for restricting production of Nanos protein to the posterior. Through an analysis of transgenes bearing multiple copies of nanos 3′UTR regulatory sequences, we provide evidence that localization of nanos RNA by components of the posteriorly localized germ plasm activates its translation by preventing interaction of nanos RNA with translational repressors. This mutually exclusive relationship between translational repression and RNA localization is mediated by a 180 nucleotide region of the nanos localization signal, containing the TCE. These studies suggest that the ability of RNA localization to direct wild-type body patterning also requires recognition of multiple, unique elements within the nanos localization signal by novel factors. Finally, we propose that differences in the efficiencies with which different RNAs are localized result from the use of temporally distinct localization pathways during oogenesis.


2000 ◽  
Vol 20 (6) ◽  
pp. 2129-2137 ◽  
Author(s):  
Sunnie R. Thompson ◽  
Elizabeth B. Goodwin ◽  
Marvin Wickens

ABSTRACT The 3′ untranslated region (3′UTR) of many eukaryotic mRNAs is essential for their control during early development. Negative translational control elements in 3′UTRs regulate pattern formation, cell fate, and sex determination in a variety of organisms.tra-2 mRNA in Caenorhabditis elegans is required for female development but must be repressed to permit spermatogenesis in hermaphrodites. Translational repression oftra-2 mRNA in C. elegans is mediated by tandemly repeated elements in its 3′UTR; these elements are called TGEs (for tra-2 and GLI element). To examine the mechanism of TGE-mediated repression, we first demonstrate that TGE-mediated translational repression occurs in Xenopus embryos and thatXenopus egg extracts contain a TGE-specific binding factor. Translational repression by the TGEs requires that the mRNA possess a poly(A) tail. We show that in C. elegans, the poly(A) tail of wild-type tra-2 mRNA is shorter than that of a mutant mRNA lacking the TGEs. To determine whether TGEs regulate poly(A) length directly, synthetic tra-2 3′UTRs with and without the TGEs were injected into Xenopus embryos. We find that TGEs accelerate the rate of deadenylation and permit the last 15 adenosines to be removed from the RNA, resulting in the accumulation of fully deadenylated molecules. We conclude that TGE-mediated translational repression involves either interference with poly(A)'s function in translation and/or regulated deadenylation.


Genetics ◽  
1996 ◽  
Vol 144 (2) ◽  
pp. 597-607 ◽  
Author(s):  
Patricia E Kuwabara

Abstract The Caenmhabditis elegans sexdetermining gene tra-2 promotes female development and expresses 4.7-, 1.9- and 1.8-kb mRNAs. The 4.7-kb mRNA encodes the major feminizing activity of the locus, a predicted membrane receptor that mediates cell-to-cell communication, named TRA-2A. The tra-2 gene was characterized from a close relative, C. briggsae. The Cb-tra-2 gene expresses only a 4.7-kb mRNA and alternatively spliced variants, which encode TRA-2A homologues. The Cb-TRA-2A and Ce-TRA-2A sequences are highly diverged, sharing only 43% identity, although their hydropathy profiles remain remarkably similar. Three potential regulatory sites of Ce-tra-2 activity were previously identified by analyzing tra-2(eg), tra-2(gf), and tra-2(mx) mutations. Two of these sites, the EG site and MX region, are consewed in Cb-tra-2. By contrast, the two direct repeat elements in the Ce-tra-2 3′ untranslated region, which are disrupted in tra-2(gf) mutants, are absent. Injection of Cb-tra-2 antisense RNA into C. briggsae mimics the Ce-tra-2 loss-of-function phenotype. Thus, antisense RNA permits studies of gene activity in nematodes that lack extensive genetics.


1988 ◽  
Vol 8 (6) ◽  
pp. 619-632 ◽  
Author(s):  
Mathias Springer ◽  
Monique Graffe ◽  
Jacques Dondon ◽  
Marianne Grunberg-Manago ◽  
Pascale Romby ◽  
...  

Genetic studies have shown that expression of the E. coli threonyl-tRNA synthetase (thrS) gene is negatively auto-regulated at the translational level. A region called the operator, located 110 nucleotides downstream of the 5′ end of the mRNA and between 10 and 50bp upstream of the translational initiation codon in the thrS gene, is directly involved in that control. The conformation of an in vitro RNA fragment extending over the thrS regulatory region has been investigated with chemical and enzymatic probes. The operator locus displays structural similarities to the anti-codon arm of threonyl tRNA. The conformation of 3 constitutent mutants containing single base changes in the operator region shows that replacement of a base in the anti-codon-like loop does not induce any conformational change, suggesting that the residue concerned is directly involved in regulation. However mutation in or close to the anti-codon-like stem results in a partial or complete rearrangement of the structure of the operator region. Further experiments indicate that there is a clear correlation between the way the synthetase recognises each operator, causing translational repression, and threonyl-tRNA.


Development ◽  
1995 ◽  
Vol 121 (6) ◽  
pp. 1775-1785 ◽  
Author(s):  
E.P. Robbie ◽  
M. Peterson ◽  
E. Amaya ◽  
T.J. Musci

Early frog embryogenesis depends on a maternal pool of mRNA to execute critical intercellular signalling events. FGF receptor-1, which is required for normal development, is stored as a stable, untranslated maternal mRNA transcript in the fully grown immature oocyte, but is translationally activated at meiotic maturation. We have identified a short cis-acting element in the FGF receptor 3′ untranslated region that inhibits translation of synthetic mRNA. This inhibitory element is sufficient to inhibit translation of heterologous reporter mRNA in the immature oocyte without changing RNA stability. Deletion of the poly(A) tract or polyadenylation signal sequences does not affect translational inhibition by this element. At meiotic maturation, we observe the reversal of translational repression mediated by the inhibitory element, mimicking that seen with endogenous maternal FGF receptor mRNA at meiosis. In addition, the activation of synthetic transcripts at maturation does not appear to require poly(A) lengthening. We also show that an oocyte cytoplasmic protein specifically binds the 3′ inhibitory element, suggesting that translational repression of Xenopus FGF receptor-1 maternal mRNA in the oocytes is mediated by RNA-protein interactions. These data describe a mechanism of translational control that appears to be independent of poly(A) changes.


Development ◽  
1999 ◽  
Vol 126 (6) ◽  
pp. 1129-1138 ◽  
Author(s):  
Y.S. Lie ◽  
P.M. Macdonald

The product of the oskar gene directs posterior patterning in the Drosophila oocyte, where it must be deployed specifically at the posterior pole. Proper expression relies on the coordinated localization and translational control of the oskar mRNA. Translational repression prior to localization of the transcript is mediated, in part, by the Bruno protein, which binds to discrete sites in the 3′ untranslated region of the oskar mRNA. To begin to understand how Bruno acts in translational repression, we performed a yeast two-hybrid screen to identify Bruno-interacting proteins. One interactor, described here, is the product of the apontic gene. Coimmunoprecipitation experiments lend biochemical support to the idea that Bruno and Apontic proteins physically interact in Drosophila. Genetic experiments using mutants defective in apontic and bruno reveal a functional interaction between these genes. Given this interaction, Apontic is likely to act together with Bruno in translational repression of oskar mRNA. Interestingly, Apontic, like Bruno, is an RNA-binding protein and specifically binds certain regions of the oskar mRNA 3′ untranslated region.


1998 ◽  
Vol 53 (11-12) ◽  
pp. 1017-1026 ◽  
Author(s):  
A. Kiinne ◽  
E. Pistorius ◽  
K. Kloppstech ◽  
E. de Groot

Abstract Two proteins with apparent molecular masses of 17 and 24 kD that are synthesized in a circadian manner in the phytoflagellate Euglena gracilis, were recognized as proteins belong­ing to the family of light-harvesting-chlorophyll-proteins (LHCPs) of class I (17 kD) and of class II (24 kD). Identification was achieved by N-terminal sequencing of the proteins isolated from two-dimensional polyacrylamide gels and by detection with an anti-LHCP II se­rum. While it was found that the total amount of LHCPs remains almost constant, when Euglena is grown under diurnal conditions (12 h light and 12 h dark), we could show that the amount of newly synthesized 17 and 24 kD proteins varies about 20-fold with a maximum of synthesis in the light phase. In contrast, the analysis of the mRNA levels at different times revealed only minor differences in the stationary concentration of the LHCP specific mRNA, indicating that the control of LHCP synthesis is at the translational level. Principally, the same finding was obtained using inhibitors of transcription. Thus, it is concluded that the expression of LHCPs in Euglena gracilis in contrast to that of higher plants is primarily regulated at the translational level.


2011 ◽  
Vol 18 (5) ◽  
pp. 564-570 ◽  
Author(s):  
Natacha Rochel ◽  
Fabrice Ciesielski ◽  
Julien Godet ◽  
Edelmiro Moman ◽  
Manfred Roessle ◽  
...  

Development ◽  
1996 ◽  
Vol 122 (9) ◽  
pp. 2791-2800 ◽  
Author(s):  
E.R. Gavis ◽  
L. Lunsford ◽  
S.E. Bergsten ◽  
R. Lehmann

Correct formation of the Drosophila body plan requires restriction of nanos activity to the posterior of the embryo. Spatial regulation of nanos is achieved by a combination of RNA localization and localization-dependent translation such that only posteriorly localized nanos RNA is translated. Cis-acting sequences that mediate both RNA localization and translational regulation lie within the nanos 3′ untranslated region. We have identified a discrete translational control element within the nanos 3′ untranslated region that acts independently of the localization signal to mediate translational repression of unlocalized nanos RNA. Both the translational regulatory function of the nanos 3′UTR and the sequence of the translational control element are conserved between D. melanogaster and D. virilis. Furthermore, we show that the RNA helicase Vasa, which is required for nanos RNA localization, also plays a critical role in promoting nanos translation. Our results specifically exclude models for translational regulation of nanos that rely on changes in polyadenylation.


1995 ◽  
Vol 129 (4) ◽  
pp. 1023-1032 ◽  
Author(s):  
J M Schumacher ◽  
K Lee ◽  
S Edelhoff ◽  
R E Braun

Previous studies in transgenic mice have established the importance of the 3' untranslated region (UTR) of the spermatid-specific protamine-1 (Prm-1) mRNA in its translational control during male germ cell development. To clone genes that mediate the translational repression or activation of the Prm-1 mRNA, we screened cDNA expression libraries made with RNA from pachytene spermatocytes and round spermatids, with an RNA probe corresponding to the 3' UTR of Prm-1. We obtained six independent clones that encode Spnr, a spermatid perinuclear RNA-binding protein. Spnr is a 71-kD protein that contains two previously described RNA binding domains. The Spnr mRNA is expressed at high levels in the testis, ovary, and brain, and is present in multiple forms in those tissues. Immunolocalization of the Spnr protein within the testis shows that it is expressed exclusively in postmeiotic germ cells and that it is localized to the manchette, a spermatid-specific microtubular array. Although the Spnr protein is expressed too late to be directly involved in the translational repression of Prm-1 specifically, we suggest that the Spnr protein may be involved in other aspects of spermatid RNA metabolism, such as RNA transport or translational activation.


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