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Hoedjes KM, Kostic H, Keller L, Flatt T. Natural alleles at the Doa locus underpin evolutionary changes in Drosophila lifespan and fecundity. Proc Biol Sci 2022; 289:20221989. [PMID: 36350205 PMCID: PMC9653240 DOI: 10.1098/rspb.2022.1989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
'Evolve and resequence' (E&R) studies in Drosophila melanogaster have identified many candidate loci underlying the evolution of ageing and life history, but experiments that validate the effects of such candidates remain rare. In a recent E&R study we have identified several alleles of the LAMMER kinase Darkener of apricot (Doa) as candidates for evolutionary changes in lifespan and fecundity. Here, we use two complementary approaches to confirm a functional role of Doa in life-history evolution. First, we used transgenic RNAi to study the effects of Doa at the whole-gene level. Ubiquitous silencing of expression in adult flies reduced both lifespan and fecundity, indicating pleiotropic effects. Second, to characterize segregating variation at Doa, we examined four candidate single nucleotide polymorphisms (SNPs; Doa-1, -2, -3, -4) using a genetic association approach. Three candidate SNPs had effects that were qualitatively consistent with expectations based on our E&R study: Doa-2 pleiotropically affected both lifespan and late-life fecundity; Doa-1 affected lifespan (but not fecundity); and Doa-4 affected late-life fecundity (but not lifespan). Finally, the last candidate allele (Doa-3) also affected lifespan, but in the opposite direction from predicted.
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Affiliation(s)
- Katja M. Hoedjes
- Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland
| | - Hristina Kostic
- Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland
| | - Laurent Keller
- Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland
| | - Thomas Flatt
- Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland,Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland
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2
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Carnesecchi J, Boumpas P, van Nierop Y Sanchez P, Domsch K, Pinto HD, Borges Pinto P, Lohmann I. The Hox transcription factor Ultrabithorax binds RNA and regulates co-transcriptional splicing through an interplay with RNA polymerase II. Nucleic Acids Res 2021; 50:763-783. [PMID: 34931250 PMCID: PMC8789087 DOI: 10.1093/nar/gkab1250] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 12/01/2021] [Accepted: 12/07/2021] [Indexed: 11/13/2022] Open
Abstract
Transcription factors (TFs) play a pivotal role in cell fate decision by coordinating gene expression programs. Although most TFs act at the DNA layer, few TFs bind RNA and modulate splicing. Yet, the mechanistic cues underlying TFs activity in splicing remain elusive. Focusing on the Drosophila Hox TF Ultrabithorax (Ubx), our work shed light on a novel layer of Ubx function at the RNA level. Transcriptome and genome-wide binding profiles in embryonic mesoderm and Drosophila cells indicate that Ubx regulates mRNA expression and splicing to promote distinct outcomes in defined cellular contexts. Our results demonstrate a new RNA-binding ability of Ubx. We find that the N51 amino acid of the DNA-binding Homeodomain is non-essential for RNA interaction in vitro, but is required for RNA interaction in vivo and Ubx splicing activity. Moreover, mutation of the N51 amino acid weakens the interaction between Ubx and active RNA Polymerase II (Pol II). Our results reveal that Ubx regulates elongation-coupled splicing, which could be coordinated by a dynamic interplay with active Pol II on chromatin. Overall, our work uncovered a novel role of the Hox TFs at the mRNA regulatory layer. This could be an essential function for other classes of TFs to control cell diversity.
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Affiliation(s)
- Julie Carnesecchi
- Heidelberg University, Centre for Organismal Studies (COS) Heidelberg, Department of Developmental Biology, Heidelberg, Germany.,Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, CNRS UMR5242, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Panagiotis Boumpas
- Heidelberg University, Centre for Organismal Studies (COS) Heidelberg, Department of Developmental Biology, Heidelberg, Germany
| | - Patrick van Nierop Y Sanchez
- Heidelberg University, Centre for Organismal Studies (COS) Heidelberg, Department of Developmental Biology, Heidelberg, Germany
| | - Katrin Domsch
- Heidelberg University, Centre for Organismal Studies (COS) Heidelberg, Department of Developmental Biology, Heidelberg, Germany.,Friedrich-Alexander-University Erlangen-Nürnberg, Department Biology, Division of Developmental Biology, Erlangen, Germany
| | - Hugo Daniel Pinto
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY, USA
| | - Pedro Borges Pinto
- Heidelberg University, Centre for Organismal Studies (COS) Heidelberg, Department of Developmental Biology, Heidelberg, Germany.,Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, CNRS UMR5242, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Ingrid Lohmann
- Heidelberg University, Centre for Organismal Studies (COS) Heidelberg, Department of Developmental Biology, Heidelberg, Germany
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3
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Mendoza-García P, Hugosson F, Fallah M, Higgins ML, Iwasaki Y, Pfeifer K, Wolfstetter G, Varshney G, Popichenko D, Gergen JP, Hens K, Deplancke B, Palmer RH. The Zic family homologue Odd-paired regulates Alk expression in Drosophila. PLoS Genet 2017; 13:e1006617. [PMID: 28369060 PMCID: PMC5393633 DOI: 10.1371/journal.pgen.1006617] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 04/17/2017] [Accepted: 02/07/2017] [Indexed: 01/30/2023] Open
Abstract
The Anaplastic Lymphoma Kinase (Alk) receptor tyrosine kinase (RTK) plays a critical role in the specification of founder cells (FCs) in the Drosophila visceral mesoderm (VM) during embryogenesis. Reporter gene and CRISPR/Cas9 deletion analysis reveals enhancer regions in and upstream of the Alk locus that influence tissue-specific expression in the amnioserosa (AS), the VM and the epidermis. By performing high throughput yeast one-hybrid screens (Y1H) with a library of Drosophila transcription factors (TFs) we identify Odd-paired (Opa), the Drosophila homologue of the vertebrate Zic family of TFs, as a novel regulator of embryonic Alk expression. Further characterization identifies evolutionarily conserved Opa-binding cis-regulatory motifs in one of the Alk associated enhancer elements. Employing Alk reporter lines as well as CRISPR/Cas9-mediated removal of regulatory elements in the Alk locus, we show modulation of Alk expression by Opa in the embryonic AS, epidermis and VM. In addition, we identify enhancer elements that integrate input from additional TFs, such as Binou (Bin) and Bagpipe (Bap), to regulate VM expression of Alk in a combinatorial manner. Taken together, our data show that the Opa zinc finger TF is a novel regulator of embryonic Alk expression. The Alk receptor tyrosine kinase is employed repeatedly during Drosophila development to drive signaling events in a variety of tissues. The spatial and temporal expression pattern of the Alk gene is tightly regulated. Identifying factors that influence the expression of Alk is important to better understand how Alk signaling is controlled. In this paper we characterize cis-regulatory sequences in the Alk locus and the transcription factors that bind them to govern Alk expression in the Drosophila embryo. Using a robotic protein-DNA interaction assay, we identified the Zic family transcription factor Odd-paired as a factor that binds to regulatory elements in the Alk locus. Binding of Odd-paired to Alkcis-regulatory elements varies spatially, revealing a requirement for additional transcription factors such as the NK3 and FoxF orthologues Bagpipe and Biniou in a subset of Alk-expressing tissues. Our findings provide new insight into the dynamics underlying temporal and spatial regulation of the Alk receptor during embryogenesis.
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Affiliation(s)
- Patricia Mendoza-García
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Fredrik Hugosson
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Mahsa Fallah
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Michael L. Higgins
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, United States of America
| | - Yasuno Iwasaki
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, United States of America
| | - Kathrin Pfeifer
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Georg Wolfstetter
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Gaurav Varshney
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | | | - J. Peter Gergen
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, United States of America
| | - Korneel Hens
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford, United Kingdom
| | - Bart Deplancke
- Laboratory of Systems Biology and Genetics, Lausanne, Switzerland
| | - Ruth H. Palmer
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- * E-mail:
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4
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D’Souza SA, Rajendran L, Bagg R, Barbier L, van Pel DM, Moshiri H, Roy PJ. The MADD-3 LAMMER Kinase Interacts with a p38 MAP Kinase Pathway to Regulate the Display of the EVA-1 Guidance Receptor in Caenorhabditis elegans. PLoS Genet 2016; 12:e1006010. [PMID: 27123983 PMCID: PMC4849719 DOI: 10.1371/journal.pgen.1006010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 04/05/2016] [Indexed: 11/25/2022] Open
Abstract
The proper display of transmembrane receptors on the leading edge of migrating cells and cell extensions is essential for their response to guidance cues. We previously discovered that MADD-4, which is an ADAMTSL secreted by motor neurons in Caenorhabditis elegans, interacts with an UNC-40/EVA-1 co-receptor complex on muscles to attract plasma membrane extensions called muscle arms. In nematodes, the muscle arm termini harbor the post-synaptic elements of the neuromuscular junction. Through a forward genetic screen for mutants with disrupted muscle arm extension, we discovered that a LAMMER kinase, which we call MADD-3, is required for the proper display of the EVA-1 receptor on the muscle’s plasma membrane. Without MADD-3, EVA-1 levels decrease concomitantly with a reduction of the late-endosomal marker RAB-7. Through a genetic suppressor screen, we found that the levels of EVA-1 and RAB-7 can be restored in madd-3 mutants by eliminating the function of a p38 MAP kinase pathway. We also found that EVA-1 and RAB-7 will accumulate in madd-3 mutants upon disrupting CUP-5, which is a mucolipin ortholog required for proper lysosome function. Together, our data suggests that the MADD-3 LAMMER kinase antagonizes the p38-mediated endosomal trafficking of EVA-1 to the lysosome. In this way, MADD-3 ensures that sufficient levels of EVA-1 are present to guide muscle arm extension towards the source of the MADD-4 guidance cue. In most animals, the physical meeting of the pre- and post-synaptic membranes of the neuromuscular junction occurs via axonal extension towards the muscle. In nematodes, however, motor axons do not extend towards the muscle and instead form a dorsal and ventral cord with relatively few branches. To make the physical connection, the body wall muscles extend membrane projections called muscle arms to the motor axons within the dorsal and ventral cords. Through previous genetic and biochemical analyses with the nematode C. elegans, we identified a neuronally-expressed muscle arm chemoattractant (MADD-4) and its muscle-expressed co-receptor complex (UNC-40/EVA-1). Here, we report our discovery of madd-3, which encodes a LAMMER kinase that is expressed in muscles to regulate muscle arm extension. Genetic analyses revealed that MADD-3 may inhibit a p38 MAP kinase pathway whose normal function is to decrease the abundance of the EVA-1 receptor. In the presence of MADD-3, the activity of the p38 pathway is relatively low, and EVA-1 levels are consequently relatively high. Without MADD-3, the p38 pathway is freed to decrease the abundance of EVA-1. The relationships that we have uncovered between MADD-3, the p38 Map Kinase pathway, and the EVA-1 receptor provide one explanation for the muscle arm defects observed in madd-3 mutants.
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Affiliation(s)
- Serena A. D’Souza
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
- The Collaborative Programme in Developmental Biology, University of Toronto, Toronto, Ontario, Canada
| | - Luckshi Rajendran
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Rachel Bagg
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Louis Barbier
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Derek M. van Pel
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Houtan Moshiri
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Peter J. Roy
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
- The Collaborative Programme in Developmental Biology, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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5
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Zhao Y, Cocco C, Domenichini S, Samson ML, Rabinow L. The IMD innate immunity pathway of Drosophila influences somatic sex determination via regulation of the Doa locus. Dev Biol 2015; 407:224-31. [DOI: 10.1016/j.ydbio.2015.09.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 08/24/2015] [Accepted: 09/24/2015] [Indexed: 11/30/2022]
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6
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Multifunctional RNA processing protein SRm160 induces apoptosis and regulates eye and genital development in Drosophila. Genetics 2014; 197:1251-65. [PMID: 24907259 DOI: 10.1534/genetics.114.164434] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
SRm160 is an SR-like protein implicated in multiple steps of RNA processing and nucleocytoplasmic export. Although its biochemical functions have been extensively described, its genetic interactions and potential participation in signaling pathways remain largely unknown, despite the fact that it is highly phosphorylated in both mammalian cells and Drosophila. To begin elucidating the functions of the protein in signaling and its potential role in developmental processes, we characterized mutant and overexpression SRm160 phenotypes in Drosophila and their interactions with the locus encoding the LAMMER protein kinase, Doa. SRm160 mutations are recessive lethal, while its overexpression generates phenotypes including roughened eyes and highly disorganized internal eye structure, which are due at least in part to aberrantly high levels of apoptosis. SRm160 is required for normal somatic sex determination, since its alleles strongly enhance a subtle sex transformation phenotype induced by Doa kinase alleles. Moreover, modification of SRm160 by DOA kinase appears to be necessary for its activity, since Doa alleles suppress phenotypes induced by SRm160 overexpression in the eye and enhance those in genital discs. Modification of SRm160 may occur through direct interaction because DOA kinase phosphorylates it in vitro. Remarkably, SRm160 protein was concentrated in the nuclei of precellular embryos but was very rapidly excluded from nuclei or degraded coincident with cellularization. Also of interest, transcripts are restricted almost exclusively to the developing nervous system in mature embryos.
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7
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Serpinskaya AS, Tuphile K, Rabinow L, Gelfand VI. Protein kinase Darkener of apricot and its substrate EF1γ regulate organelle transport along microtubules. J Cell Sci 2013; 127:33-9. [PMID: 24163433 DOI: 10.1242/jcs.123885] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Regulation of organelle transport along microtubules is important for proper distribution of membrane organelles and protein complexes in the cytoplasm. RNAi-mediated knockdown in cultured Drosophila S2 cells demonstrates that two microtubule-binding proteins, a unique isoform of Darkener of apricot (DOA) protein kinase, and its substrate, translational elongation factor EF1γ, negatively regulate transport of several classes of membrane organelles along microtubules. Inhibition of transport by EF1γ requires its phosphorylation by DOA on serine 294. Together, our results indicate a new role for two proteins that have not previously been implicated in regulation of the cytoskeleton. These results further suggest that the biological role of some of the proteins binding to the microtubule track is to regulate cargo transport along these tracks.
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Affiliation(s)
- Anna S Serpinskaya
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 616011, USA
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8
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Zhao S, Chen D, Geng Q, Wang Z. The highly conserved LAMMER/CLK2 protein kinases prevent germ cell overproliferation in Drosophila. Dev Biol 2013; 376:163-70. [DOI: 10.1016/j.ydbio.2013.01.023] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 01/14/2013] [Accepted: 01/23/2013] [Indexed: 10/27/2022]
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9
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Marquez Y, Brown JWS, Simpson C, Barta A, Kalyna M. Transcriptome survey reveals increased complexity of the alternative splicing landscape in Arabidopsis. Genome Res 2012; 22:1184-95. [PMID: 22391557 PMCID: PMC3371709 DOI: 10.1101/gr.134106.111] [Citation(s) in RCA: 553] [Impact Index Per Article: 46.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Alternative splicing (AS) is a key regulatory mechanism that contributes to transcriptome and proteome diversity. As very few genome-wide studies analyzing AS in plants are available, we have performed high-throughput sequencing of a normalized cDNA library which resulted in a high coverage transcriptome map of Arabidopsis. We detect ∼150,000 splice junctions derived mostly from typical plant introns, including an eightfold increase in the number of U12 introns (2069). Around 61% of multiexonic genes are alternatively spliced under normal growth conditions. Moreover, we provide experimental validation of 540 AS transcripts (from 256 genes coding for important regulatory factors) using high-resolution RT-PCR and Sanger sequencing. Intron retention (IR) is the most frequent AS event (∼40%), but many IRs have relatively low read coverage and are less well-represented in assembled transcripts. Additionally, ∼51% of Arabidopsis genes produce AS transcripts which do not involve IR. Therefore, the significance of IR in generating transcript diversity was generally overestimated in previous assessments. IR analysis allowed the identification of a large set of cryptic introns inside annotated coding exons. Importantly, a significant fraction of these cryptic introns are spliced out in frame, indicating a role in protein diversity. Furthermore, we show extensive AS coupled to nonsense-mediated decay in AFC2, encoding a highly conserved LAMMER kinase which phosphorylates splicing factors, thus establishing a complex loop in AS regulation. We provide the most comprehensive analysis of AS to date which will serve as a valuable resource for the plant community to study transcriptome complexity and gene regulation.
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Affiliation(s)
- Yamile Marquez
- Max F. Perutz Laboratories, Medical University of Vienna, Vienna, Austria
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10
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LAMMER kinase Kic1 is involved in pre-mRNA processing. Exp Cell Res 2011; 317:2308-20. [PMID: 21745468 DOI: 10.1016/j.yexcr.2011.06.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2011] [Revised: 06/22/2011] [Accepted: 06/23/2011] [Indexed: 01/03/2023]
Abstract
The LAMMER kinases are conserved through evolution. They play vital roles in cell growth/differentiation, development, and metabolism. One of the best known functions of the kinases in animal cells is the regulation of pre-mRNA splicing. Kic1 is the LAMMER kinase in fission yeast Schizosaccharomyces pombe. Despite the reported pleiotropic effects of kic1+ deletion/overexpression on various cellular processes the involvement of Kic1 in splicing remains elusive. In this study, we demonstrate for the first time that Kic1 not only is required for efficient splicing but also affects mRNA export, providing evidence for the conserved roles of LAMMER kinases in the unicellular context of fission yeast. Consistent with the hypothesis of its direct participation in multiple steps of pre-mRNA processing, Kic1 is predominantly present in the nucleus during interphase. In addition, the kinase activity of Kic1 plays a role in modulating its own cellular partitioning. Interestingly, Kic1 expression oscillates in a cell cycle-dependent manner and the peak level coincides with mitosis and cytokinesis, revealing a potential mechanism for controlling the kinase activity during the cell cycle. The novel information about the in vivo functions and regulation of Kic1 offers insights into the conserved biological roles fundamental to LAMMER kinases in eukaryotes.
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11
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Rabinow L, Samson ML. The role of the Drosophila LAMMER protein kinase DOA in somatic sex determination. J Genet 2010; 89:271-7. [DOI: 10.1007/s12041-010-0038-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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12
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Drosophila translational elongation factor-1gamma is modified in response to DOA kinase activity and is essential for cellular viability. Genetics 2009; 184:141-54. [PMID: 19841092 DOI: 10.1534/genetics.109.109553] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Drosophila translational elongation factor-1gamma (EF1gamma) interacts in the yeast two-hybrid system with DOA, the LAMMER protein kinase of Drosophila. Analysis of mutant EF1gamma alleles reveals that the locus encodes a structurally conserved protein essential for both organismal and cellular survival. Although no genetic interactions were detected in combinations with mutations in EF1alpha, an EF1gamma allele enhanced mutant phenotypes of Doa alleles. A predicted LAMMER kinase phosphorylation site conserved near the C terminus of all EF1gamma orthologs is a phosphorylation site in vitro for both Drosophila DOA and tobacco PK12 LAMMER kinases. EF1gamma protein derived from Doa mutant flies migrates with altered mobility on SDS gels, consistent with it being an in vivo substrate of DOA kinase. However, the aberrant mobility appears to be due to a secondary protein modification, since the mobility of EF1gamma protein obtained from wild-type Drosophila is unaltered following treatment with several nonspecific phosphatases. Expression of a construct expressing a serine-to-alanine substitution in the LAMMER kinase phosphorylation site into the fly germline rescued null EF1gamma alleles but at reduced efficiency compared to a wild-type construct. Our data suggest that EF1gamma functions in vital cellular processes in addition to translational elongation and is a LAMMER kinase substrate in vivo.
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13
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James BP, Staatz WD, Wilkinson ST, Meuillet E, Powis G. Superoxide dismutase is regulated by LAMMER kinase in Drosophila and human cells. Free Radic Biol Med 2009; 46:821-7. [PMID: 19135146 PMCID: PMC2699669 DOI: 10.1016/j.freeradbiomed.2008.12.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Revised: 12/08/2008] [Accepted: 12/12/2008] [Indexed: 11/30/2022]
Abstract
LAMMER kinases (also known as CDC-2-like or CLKs) are a family of dual specificity serine/threonine protein kinases that are found in all sequenced eukaryotic genomes. In the fission yeast, Schizosaccharomyces pombe, the LAMMER kinase gene, Lkh1, positively regulates the expression of the antioxidant defense genes, superoxide dismutase 1 (sod1+, CuZn-SOD) and catalase (ctt1+, CAT). We have shown that mutations in the Drosophila LAMMER kinase gene, Darkener of apricot (Doa), protect against the decrease in life span caused by the reactive oxygen species (ROS) generator paraquat, and at the same time show an increase in cytoplasmic (CuZn-Sod or SOD1) and mitochondrial superoxide dismutase (Mn-Sod or SOD2) protein levels and activity. The siRNA-mediated knock down of the human LAMMER kinase gene, CLK-1, in HeLa and MCF-7 human cell lines leads to an increase in both SOD1 activity and mRNA transcript levels. These data suggest that SOD1 is negatively regulated by LAMMER kinases in Drosophila and human cell lines and that this regulation may be conserved during evolution.
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Affiliation(s)
- Brian P James
- Department of Experimental Therapeutics, M.D. Anderson Cancer Center, 1400 Holcombe Blvd., Y6.6032, Unit 36, Houston, TX 77030, USA.
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14
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Abstract
The Darkener of apricot (Doa) locus of Drosophila encodes a LAMMER protein kinase affecting alterative splicing, and hence sex determination, via the phosphorylation of SR and SR-like proteins. Doa encodes 6 different kinases via alternative promoter usage. To provide further insight into the roles of the multiple isoforms, we mapped polymorphisms, deletions, and P-element insertions in the locus, identifying several that are largely, if not completely, isoform specific in their effects. These tests, along with the use of lines permitting overexpression and interfering RNA expression, demonstrate that the major isoforms of 55 and 105 kDa perform separate functions. The 105-kDa and a minor 138-kDa isoform are both vital but do not apparently perform functions essential for sex determination. Curiously, male-specific lethality induced by overexpression of the 55-kDa kinase in the larval fat body is rescued by coexpression of TRA, suggesting a sex-specific physiological role for this isoform. Maternal effects in which the survival of heteroallelic adults depends upon the direction of the cross are consistent with a role for a 105-kDa cytoplasmic kinase in oogenesis or early larval development.
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