The mei-P26 Gene Encodes a RING Finger B-box Coiled-Coil-NHL Protein That Regulates Seizure Susceptibility in Drosophilia

Glasscock, Edward; Singhania, Ayush; Tanouye, Mark A.

doi:10.1534/genetics.105.043174

Cited by 23 publications

(18 citation statements)

References 41 publications

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“…The mei-p26 gene has a very large gene body size of nearly 30 kb, and five different transcripts have been identified (20,21). Mei-p26 is involved in germ cell development in Drosophila (22)(23)(24).…”

Section: Discussionmentioning

confidence: 99%

Major spliceosome defects cause male infertility and are associated with nonobstructive azoospermia in humans

Sun

Wen

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Processing of pre-mRNA into mRNA is an important regulatory mechanism in eukaryotes that is mediated by the spliceosome, a huge and dynamic ribonucleoprotein complex. Splicing defects are implicated in a spectrum of human disease, but the underlying mechanistic links remain largely unresolved. Using a genome-wide association approach, we have recently identified single nucleotide polymorphisms in humans that associate with nonobstructive azoospermia (NOA), a common cause of male infertility. Here, using genetic manipulation of corresponding candidate loci in Drosophila, we show that the spliceosome component SNRPA1/U2A is essential for male fertility. Loss of U2A in germ cells of the Drosophila testis does not affect germline stem cells, but does result in the accumulation of mitotic spermatogonia that fail to differentiate into spermatocytes and mature sperm. Lack of U2A causes insufficient splicing of mRNAs required for the transition of germ cells from proliferation to differentiation. We show that germ cellspecific disruption of other components of the major spliceosome manifests with the same phenotype, demonstrating that mRNA processing is required for the differentiation of spermatogonia. This requirement is conserved, and expression of human SNRPA1 fully restores spermatogenesis in U2A mutant flies. We further report that several missense mutations in human SNRPA1 that inhibit the assembly of the major spliceosome dominantly disrupt spermatogonial differentiation in Drosophila. Collectively, our findings uncover a conserved and specific requirement for the major spliceosome during the transition from spermatogonial proliferation to differentiation in the male testis, suggesting that spliceosome defects affecting the differentiation of human spermatogonia contribute to NOA.

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Section: Discussionmentioning

confidence: 99%

Major spliceosome defects cause male infertility and are associated with nonobstructive azoospermia in humans

Sun

Wen

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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“…In any case, our conclusion that the LGMD2H mutation in the NHL domain inactivates Trim32 is consistent with published reports of other NHL-containing TRIM family proteins. Thus, Drosophila mei-P26, a putative Trim32 homolog, is inactivated by a missense mutation at a conserved residue in its NHL domain, leading to a neurological seizure phenotype (46). Similarly, missense point mutations in the NHL domain of Caenorhabditis LIN-41 also inactivate the protein, leading to an altered developmental phenotype (36).…”

Section: Discussionmentioning

confidence: 99%

The Interaction of Piasy with Trim32, an E3-Ubiquitin Ligase Mutated in Limb-girdle Muscular Dystrophy Type 2H, Promotes Piasy Degradation and Regulates UVB-induced Keratinocyte Apoptosis through NFκB

Albor

El-Hizawi

Horn

et al. 2006

Journal of Biological Chemistry

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Protein inhibitors of activated STATs (PIAS) family members are ubiquitin-protein isopeptide ligase-small ubiquitin-like modifier ligases for diverse transcription factors. However, the regulation of PIAS protein activity in cells is poorly understood. Previously, we reported that expression of Trim32, a RING domain ubiquitin-protein isopeptide ligase-ubiquitin ligase mutated in human limb-girdle muscular dystrophy type 2H (LGMD2H) and Bardet-Biedl syndrome, is elevated during mouse skin carcinogenesis, protecting keratinocytes from apoptosis induced by UVB and tumor necrosis factor-␣ (TNF␣). Here we report that Trim32 interacts with Piasy and promotes Piasy ubiquitination and degradation. Ubiquitination of Piasy by Trim32 could be reproduced in vitro using purified components. Their interaction was induced by treatment with UVB/ TNF␣ and involved redistribution of Piasy from the nucleus to the cytoplasm, where it accumulated in cytoplasmic granules that colocalized with Trim32. Piasy destabilization and ubiquitination required an intact RING domain in Trim32. The LGMD2H-associated missense point mutation prevented Trim32 binding to Piasy, and human Piasy failed to colocalize with human Trim32 in fibroblasts isolated from an LGMD2H patient. Trim32 expression increased the transcriptional activity of NFB in epidermal keratinocytes, both under basal treatment and after UVB/TNF␣ treatment. Conversely, Piasy inhibited NFB activity under the same conditions and sensitized keratinocytes to apoptosis induced by TNF␣ and UVB. Our results indicate that, by controlling Piasy stability, Trim32 regulates UVB-induced keratinocyte apoptosis through induction of NFB and suggests loss of function of Trim32 in LGMD2H.Protein ubiquitination is a fundamental process in eukaryotic cells, controlling the degradation of proteins through the 26 S proteasome. E3 4 -ubiquitin ligases catalyze the last step of the process and provide substrate specificity. The activity of many cellular factors is controlled by their abundance and stability in the cell, properties that depend on the rate of ubiquitination. By providing substrate specificity, E3 ligases become a point of control for ubiquitination and stability of many cellular factors. A variety of otherwise structurally unrelated E3 ligases contain a common RING domain that provides interaction with the E2 ubiquitin-conjugating enzyme (1). In Trim32, the RING domain is present in the amino terminus of the protein, as part of the RBCC (Ring/B-Box/Coiled-coil) or tripartite motif that defines the TRIM family of proteins (2). Members of the TRIM family may be located in the cytoplasm or nucleus and are thought to form large multimeric complexes, forming subcellular structures resembling spheres, speckles, or ribbons. Different TRIM family members are characterized by a specific carboxyl-terminal domain. In Trim32, the carboxyl terminus contains six repeats of the NHL (NCL-1, HT2A and LIN-41) motif, thought to mediate protein/protein interactions (3). TRIM family members have been implicated...

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“…vas and mei-P26 interact genetically Among the mRNAs we recovered was mei-P26, which has been implicated in germ cell differentiation in both sexes, and which also functions somatically in the nervous system (Page et al 2000;Glasscock et al 2005;Neumü ller et al 2008). Mei-P26, a TRIM-NHL domain protein, interacts with Argonaute-1 (AGO1), inhibiting the microRNA (miRNA) pathway and promoting differentiation of early-stage committed germline cells (Neumü ller et al 2008).…”

Section: Isolation Of Vas-associated Mrnasmentioning

confidence: 99%

Vasa promotes Drosophila germline stem cell differentiation by activating mei-P26 translation by directly interacting with a (U)-rich motif in its 3′ UTR

Liu

Han²,

Lasko³

2009

Genes Dev.

104

105

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Vasa (Vas) is a DEAD-box RNA-binding protein required in Drosophila at several steps of oogenesis and for primordial germ cell (PGC) specification. Vas associates with eukaryotic initiation factor 5B (eIF5B), and this interaction has been implicated in translational activation of gurken mRNA in the oocyte. Vas is expressed in all ovarian germline cells, and aspects of the vas-null phenotype suggest a function in regulating the balance between germline stem cells (GSCs) and their fate-restricted descendants. We used a biochemical approach to recover Vas-associated mRNAs and obtained mei-P26, whose product represses microRNA activity and promotes GSC differentiation. We found that vas and mei-P26 mutants interact, and that mei-P26 translation is substantially reduced in vas mutant cells. In vitro, Vas protein bound specifically to a (U)-rich motif in the mei-P26 39 untranslated region (UTR), and Vas-dependent regulation of GFP-mei-P26 transgenes in vivo was dependent on the same (U)-rich 39 UTR domain. The ability of Vas to activate mei-P26 expression in vivo was abrogated by a mutation that greatly reduces its interaction with eIF5B. Taken together, our data support the conclusion that Vas promotes germ cell differentiation by directly activating mei-P26 translation in early-stage committed cells.[Keywords: Oogenesis; RNA-binding protein; DEAD-box; patterning; development] Supplemental material is available at http://www.genesdev.org.

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The mei-P26 Gene Encodes a RING Finger B-box Coiled-Coil-NHL Protein That Regulates Seizure Susceptibility in Drosophilia

Cited by 23 publications

References 41 publications

Major spliceosome defects cause male infertility and are associated with nonobstructive azoospermia in humans

Major spliceosome defects cause male infertility and are associated with nonobstructive azoospermia in humans

The Interaction of Piasy with Trim32, an E3-Ubiquitin Ligase Mutated in Limb-girdle Muscular Dystrophy Type 2H, Promotes Piasy Degradation and Regulates UVB-induced Keratinocyte Apoptosis through NFκB

Vasa promotes Drosophila germline stem cell differentiation by activating mei-P26 translation by directly interacting with a (U)-rich motif in its 3′ UTR

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