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Taylor M, Marx O, Norris A. TDP-1 and FUST-1 co-inhibit exon inclusion and control fertility together with transcriptional regulation. Nucleic Acids Res 2023; 51:9610-9628. [PMID: 37587694 PMCID: PMC10570059 DOI: 10.1093/nar/gkad665] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 07/20/2023] [Accepted: 08/09/2023] [Indexed: 08/18/2023] Open
Abstract
Gene expression is a multistep process and crosstalk among regulatory layers plays an important role in coordinating gene expression. To identify functionally relevant gene expression coordination, we performed a systematic reverse-genetic interaction screen in C. elegans, combining RNA binding protein (RBP) and transcription factor (TF) mutants to generate over 100 RBP;TF double mutants. We identified many unexpected double mutant phenotypes, including two strong genetic interactions between the ALS-related RBPs, fust-1 and tdp-1, and the homeodomain TF ceh-14. Losing any one of these genes alone has no effect on the health of the organism. However, fust-1;ceh-14 and tdp-1;ceh-14 double mutants both exhibit strong temperature-sensitive fertility defects. Both double mutants exhibit defects in gonad morphology, sperm function, and oocyte function. RNA-Seq analysis of double mutants identifies ceh-14 as the main controller of transcript levels, while fust-1 and tdp-1 control splicing through a shared role in exon inhibition. A skipped exon in the polyglutamine-repeat protein pqn-41 is aberrantly included in tdp-1 mutants, and genetically forcing this exon to be skipped in tdp-1;ceh-14 double mutants rescues their fertility. Together our findings identify a novel shared physiological role for fust-1 and tdp-1 in promoting C. elegans fertility and a shared molecular role in exon inhibition.
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Affiliation(s)
- Morgan Taylor
- Southern Methodist University, Dallas, TX 75205, USA
| | - Olivia Marx
- Southern Methodist University, Dallas, TX 75205, USA
| | - Adam Norris
- Southern Methodist University, Dallas, TX 75205, USA
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2
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Taylor M, Marx O, Norris A. TDP-1 and FUST-1 co-inhibit exon inclusion and control fertility together with transcriptional regulation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.18.537345. [PMID: 37131843 PMCID: PMC10153140 DOI: 10.1101/2023.04.18.537345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Gene expression is a multistep, carefully controlled process, and crosstalk between regulatory layers plays an important role in coordinating gene expression. To identify functionally relevant coordination between transcriptional and post-transcriptional gene regulation, we performed a systematic reverse-genetic interaction screen in C. elegans . We combined RNA binding protein (RBP) and transcription factor (TF) mutants, creating over 100 RBP; TF double mutants. This screen identified a variety of unexpected double mutant phenotypes, including two strong genetic interactions between the ALS-related RBPs, fust-1 and tdp-1 , and the homeodomain TF ceh-14 . Losing any one of these genes alone has no significant effect on the health of the organism. However, fust-1; ceh-14 and tdp-1; ceh-14 double mutants both exhibit strong temperature-sensitive fertility defects. Both double mutants exhibit defects in gonad morphology, sperm function, and oocyte function. RNA-seq analysis of double mutants identifies ceh-14 as the main controller of transcript levels, while fust-1 and tdp-1 control splicing through a shared role in exon inhibition. We identify a cassette exon in the polyglutamine-repeat protein pqn-41 which tdp-1 inhibits. Loss of tdp-1 causes the pqn-41 exon to be aberrantly included, and forced skipping of this exon in tdp-1; ceh-14 double mutants rescues fertility. Together our findings identify a novel shared physiological role for fust-1 and tdp-1 in promoting C. elegans fertility in a ceh-14 mutant background and reveal a shared molecular function of fust-1 and tdp-1 in exon inhibition.
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Paschinger K, Wöls F, Yan S, Jin C, Vanbeselaere J, Dutkiewicz Z, Arcalis E, Malzl D, Wilson IBH. N-glycan antennal modifications are altered in Caenorhabditis elegans lacking the HEX-4 N-acetylgalactosamine-specific hexosaminidase. J Biol Chem 2023; 299:103053. [PMID: 36813232 PMCID: PMC10060765 DOI: 10.1016/j.jbc.2023.103053] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 02/16/2023] [Accepted: 02/17/2023] [Indexed: 02/24/2023] Open
Abstract
Simple organisms are often considered to have simple glycomes, but plentiful paucimannosidic and oligomannosidic glycans overshadow the less abundant N-glycans with highly variable core and antennal modifications; Caenorhabditis elegans is no exception. By use of optimized fractionation and assessing wildtype in comparison to mutant strains lacking either the HEX-4 or HEX-5 β-N-acetylgalactosaminidases, we conclude that the model nematode has a total N-glycomic potential of 300 verified isomers. Three pools of glycans were analyzed for each strain: either PNGase F released and eluted from a reversed-phase C18 resin with either water or 15% methanol or PNGase Ar released. While the water-eluted fractions were dominated by typical paucimannosidic and oligomannosidic glycans and the PNGase Ar-released pools by glycans with various core modifications, the methanol-eluted fractions contained a huge range of phosphorylcholine-modified structures with up to three antennae, sometimes with four N-acetylhexosamine residues in series. There were no major differences between the C. elegans wildtype and hex-5 mutant strains, but the hex-4 mutant strains displayed altered sets of methanol-eluted and PNGase Ar-released pools. In keeping with the specificity of HEX-4, there were more glycans capped with N-acetylgalactosamine in the hex-4 mutants, as compared with isomeric chito-oligomer motifs in the wildtype. Considering that fluorescence microscopy showed that a HEX-4::enhanced GFP fusion protein colocalizes with a Golgi tracker, we conclude that HEX-4 plays a significant role in late-stage Golgi processing of N-glycans in C. elegans. Furthermore, finding more "parasite-like" structures in the model worm may facilitate discovery of glycan-processing enzymes occurring in other nematodes.
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Affiliation(s)
| | - Florian Wöls
- Department für Chemie, Universität für Bodenkultur, Wien, Austria
| | - Shi Yan
- Department für Chemie, Universität für Bodenkultur, Wien, Austria; Institut für Parasitologie, Veterinärmedizinische Universität, Wien, Austria
| | - Chunsheng Jin
- Institutionen för Biomedicin, Göteborgs universitet, Göteborg, Sweden
| | | | | | - Elsa Arcalis
- Department für angewandte Genetik und Zellbiologie, Universität für Bodenkultur, Wien, Austria
| | - Daniel Malzl
- Department für Chemie, Universität für Bodenkultur, Wien, Austria
| | - Iain B H Wilson
- Department für Chemie, Universität für Bodenkultur, Wien, Austria.
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Cao R, Li JX, Chen H, Cao C, Zheng F, Huang K, Chen YR, Flitsch SL, Liu L, Voglmeir J. Complete shift in glycosyl donor specificity in mammalian, but not C. elegans β1,4‐GalT1 Y286L mutants, enables the synthesis of N,N‐diacetyllactosamine. ChemCatChem 2022. [DOI: 10.1002/cctc.202101699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Ran Cao
- Nanjing Agricultural University College of Food Science And Technology CHINA
| | - Jing-Xuan Li
- Nanjing Agricultural University College of Food Science And Technology CHINA
| | - Huan Chen
- Nanjing Agricultural University College of Food Science And Technology CHINA
| | - Cui Cao
- Nanjing Agricultural University College of Food Science And Technology CHINA
| | - Feng Zheng
- Nanjing Agricultural University College of Food Science And Technology CHINA
| | - Kun Huang
- Nanjing Agricultural University College of Food Science And Technology UNITED KINGDOM
| | - Ya-Ran Chen
- Nanjing Agricultural University College of Food Science And Technology CHINA
| | | | - Li Liu
- Nanjing Agricultural University College of Food Science And Technology CHINA
| | - Josef Voglmeir
- Nanjing Agricultural University College of Food Science And Technology 1 Weigang 210095 Nanjing CHINA
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Abstract
Establishment of neural circuits requires reproducible and precise interactions between growing axons, dendrites and their tissue environment. Cell adhesion molecules and guidance factors are involved in the process, but how specificity is achieved remains poorly understood. Glycans are the third major class of biopolymers besides nucleic acids and proteins, and are usually covalently linked to proteins to form glycoconjugates. Common to most glycans is an extraordinary level of molecular diversity, making them attractive candidates to contribute specificity during neural development. Indeed, many genes important for neural development encode glycoproteins, or enzymes involved in synthesizing or modifying glycans. Glycoconjugates are classified based on both the types of glycans and type of attachment that link them to proteins. Here I discuss progress in understanding the function of glycans, glycan modifications and glycoconjugates during neural development in Caenorhabditis elegans. I will also highlight relevance to human disease and known roles of glycoconjugates in regeneration.
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Affiliation(s)
- Hannes E Bülow
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, United States; Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, United States.
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Bombyx mori β1,4-N-acetylgalactosaminyltransferase possesses relaxed donor substrate specificity in N-glycan synthesis. Sci Rep 2021; 11:5505. [PMID: 33750826 PMCID: PMC7943597 DOI: 10.1038/s41598-021-84771-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 02/08/2021] [Indexed: 12/15/2022] Open
Abstract
N-Glycosylation is one of the most important post-translational protein modifications in eukaryotic cells. Although more than 200 N-glycogenes contributing to N-glycan biosynthesis have been identified and characterized, the information on insect N-glycosylation is still limited. Here, focusing on insect N-glycosylation, we characterized Bombyx mori N-acetylgalactosaminyltransferase (BmGalNAcT) participating in complex N-glycan biosynthesis in mammals. BmGalNAcT localized at the Golgi and was ubiquitously expressed in every organ and in the developmental stage of the middle silk gland of fifth instar larvae. Analysis of recombinant BmGalNAcT expressed in Sf9 cells showed that BmGalNAcT transferred GalNAc to non-reducing terminals of GlcNAcβ1,2-R with β1,4-linkage. In addition, BmGalNAcT mediated transfer of galactose and N-acetylglucosamine residues but not transfer of either glucose or glucuronic acid from the UDP-sugar donor substrate to the N-glycan. Despite this tri-functional sugar transfer activity, however, most of the endogenous glycoproteins of insect cells were present without GalNAc, Gal, or GlcNAc residues at the non-reducing terminal of β1,2-GlcNAc residue(s). Moreover, overexpression of BmGalNAcT in insect cells had no effect on N-acetylgalactosaminylation, galactosylation, or N-acetylglucosaminylation of the major N-glycan during biosynthesis. These results suggested that B. mori has a novel multifunctional glycosyltransferase, but the N-glycosylation is highly and strictly regulated by the endogenous N-glycosylation machineries.
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Yan S, Wang H, Schachter H, Jin C, Wilson IBH, Paschinger K. Ablation of N-acetylglucosaminyltransferases in Caenorhabditis induces expression of unusual intersected and bisected N-glycans. Biochim Biophys Acta Gen Subj 2018; 1862:2191-2203. [PMID: 29981898 PMCID: PMC6173287 DOI: 10.1016/j.bbagen.2018.07.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 06/30/2018] [Accepted: 07/04/2018] [Indexed: 12/17/2022]
Abstract
The modification in the Golgi of N-glycans by N-acetylglucosaminyltransferase I (GlcNAc-TI, MGAT1) can be considered to be a hallmark of multicellular eukaryotes as it is found in all metazoans and plants, but rarely in unicellular organisms. The enzyme is key for the normal processing of N-glycans to either complex or paucimannosidic forms, both of which are found in the model nematode Caenorhabditis elegans. Unusually, this organism has three different GlcNAc-TI genes (gly-12, gly-13 and gly-14); therefore, a complete abolition of GlcNAc-TI activity required the generation of a triple knock-out strain. Previously, the compositions of N-glycans from this mutant were described, but no detailed structures. Using an off-line HPLC-MALDI-TOF-MS approach combined with exoglycosidase digestions and MS/MS, we reveal that the multiple hexose residues of the N-glycans of the gly-12;gly-13;gly-14 triple mutant are not just mannose, but include galactoses in three different positions (β-intersecting, β-bisecting and α-terminal) on isomeric forms of Hex4-8HexNAc2 structures; some of these structures are fucosylated and/or methylated. Thus, the N-glycomic repertoire of Caenorhabditis is even wider than expected and exhibits a large degree of plasticity even in the absence of key glycan processing enzymes from the Golgi apparatus.
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Affiliation(s)
- Shi Yan
- Department für Chemie, Universität für Bodenkultur, 1190 Wien, Austria,Institut für Parasitologie, Veterinärmedizinische Universität Wien, 1210 Wien, Austria
| | - Huijie Wang
- Department für Chemie, Universität für Bodenkultur, 1190 Wien, Austria
| | - Harry Schachter
- Hospital for Sick Children and University of Toronto, Toronto, ON M5G 1X8, Canada
| | - Chunsheng Jin
- Institutionen för Biomedicin, Göteborgs universitet, 405 30 Göteborg, Sweden
| | - Iain B. H. Wilson
- Department für Chemie, Universität für Bodenkultur, 1190 Wien, Austria,To whom correspondence should be addressed:
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