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Kin K, Chen ZH, Forbes G, Lawal H, Schilde C, Singh R, Cole C, Barton GJ, Schaap P. The protein kinases of Dictyostelia and their incorporation into a signalome. Cell Signal 2023; 108:110714. [PMID: 37187217 DOI: 10.1016/j.cellsig.2023.110714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 05/02/2023] [Accepted: 05/12/2023] [Indexed: 05/17/2023]
Abstract
Protein kinases are major regulators of cellular processes, but the roles of most kinases remain unresolved. Dictyostelid social amoebas have been useful in identifying functions for 30% of its kinases in cell migration, cytokinesis, vesicle trafficking, gene regulation and other processes but their upstream regulators and downstream effectors are mostly unknown. Comparative genomics can assist to distinguish between genes involved in deeply conserved core processes and those involved in species-specific innovations, while co-expression of genes as evident from comparative transcriptomics can provide cues to the protein complement of regulatory networks. Genomes and developmental and cell-type specific transcriptomes are available for species that span the 0.5 billion years of evolution of Dictyostelia from their unicellular ancestors. In this work we analysed conservation and change in the abundance, functional domain architecture and developmental regulation of protein kinases across the 4 major taxon groups of Dictyostelia. All data are summarized in annotated phylogenetic trees of the kinase subtypes and accompanied by functional information of all kinases that were experimentally studied. We detected 393 different protein kinase domains across the five studied genomes, of which 212 were fully conserved. Conservation was highest (71%) in the previously defined AGC, CAMK, CK1, CMCG, STE and TKL groups and lowest (26%) in the "other" group of typical protein kinases. This was mostly due to species-specific single gene amplification of "other" kinases. Apart from the AFK and α-kinases, the atypical protein kinases, such as the PIKK and histidine kinases were also almost fully conserved. The phylogeny-wide developmental and cell-type specific expression profiles of the protein kinase genes were combined with profiles from the same transcriptomic experiments for the families of G-protein coupled receptors, small GTPases and their GEFs and GAPs, the transcription factors and for all genes that upon lesion generate a developmental defect. This dataset was subjected to hierarchical clustering to identify clusters of co-expressed genes that potentially act together in a signalling network. The work provides a valuable resource that allows researchers to identify protein kinases and other regulatory proteins that are likely to act as intermediates in a network of interest.
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Affiliation(s)
- Koryu Kin
- Molecular Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom; Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Barcelona, Spain.
| | - Zhi-Hui Chen
- Molecular Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom
| | - Gillian Forbes
- Molecular Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom; Institut de Génomique Fonctionnelle de Lyon (IGFL), CNRS, École Normale Supérieure de Lyon and Université Claude Bernard Lyon-1, Lyon 69007, France.
| | - Hajara Lawal
- Molecular Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom
| | - Christina Schilde
- Molecular Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom; D'Arcy Thompson Unit, School of Life Sciences, University of Dundee, DD1 4HN, United Kingdom.
| | - Reema Singh
- Molecular Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom; Computational Biology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom; Vaccine and Infectious Disease Organization, University of Saskatchewan,120 Veterinary Road, Saskatoon, SK S7N 5E3, Canada.
| | - Christian Cole
- Computational Biology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom; Population Health and Genomics, School of Medicine, University of Dundee, Ninewells Hospital, Dundee DD1 9SY, United Kingdom
| | - Geoffrey J Barton
- Computational Biology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom
| | - Pauline Schaap
- Molecular Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom.
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Du Q, Schaap P. Autophagy of the somatic stalk cells likely nurses the propagating spores of Dictyostelid social amoebas. OPEN RESEARCH EUROPE 2022; 2:104. [PMID: 36860212 PMCID: PMC7614253 DOI: 10.12688/openreseurope.14947.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 11/14/2022] [Indexed: 11/24/2022]
Abstract
Background: Autophagy (self-feeding) assists survival of starving cells by partial self-digestion, while dormancy as cysts, spores or seeds enables long-term survival. Starving Dictyostelium amoebas construct multicellular fruiting bodies with spores and stalk cells, with many Dictyostelia still able to encyst individually like their single-celled ancestors. While autophagy mostly occurs in the somatic stalk cells, autophagy gene knock-outs in Dictyostelium discoideum ( D. discoideum) formed no spores and lacked cAMP induction of prespore gene expression. Methods: To investigate whether autophagy also prevents encystation, we knocked-out autophagy genes atg5 and atg7 in the dictyostelid Polysphondylium pallidum, which forms both spores and cysts. We measured spore and cyst differentiation and viability in the knock-out as well as stalk and spore gene expression and its regulation by cAMP. We tested a hypothesis that spores require materials derived from autophagy in stalk cells. Sporulation requires secreted cAMP acting on receptors and intracellular cAMP acting on PKA. We compared the morphology and viability of spores developed in fruiting bodies with spores induced from single cells by stimulation with cAMP and 8Br-cAMP, a membrane-permeant PKA agonist. Results: Loss of autophagy in P. pallidum reduced but did not prevent encystation. Stalk cells still differentiated but stalks were disorganised. However, no spores were formed at all and cAMP-induced prespore gene expression was lost. D. discoideum spores induced in vitro by cAMP and 8Br-cAMP were smaller and rounder than spores formed multicellularly and while they were not lysed by detergent they germinated not (strain Ax2) or poorly (strain NC4), unlike spores formed in fruiting bodies. Conclusions: The stringent requirement of sporulation on both multicellularity and autophagy, which occurs mostly in stalk cells, suggests that stalk cells nurse the spores through autophagy. This highlights autophagy as a major cause for somatic cell evolution in early multicellularity.
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Affiliation(s)
- Qingyou Du
- School of Life Sciences, University of Dundee, Dundee, Angus, DD15EH, UK
| | - Pauline Schaap
- School of Life Sciences, University of Dundee, Dundee, Angus, DD15EH, UK
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Kin K, Chen ZH, Forbes G, Schaap P. Evolution of a novel cell type in Dictyostelia required gene duplication of a cudA-like transcription factor. Curr Biol 2022; 32:428-437.e4. [PMID: 34883046 PMCID: PMC8808424 DOI: 10.1016/j.cub.2021.11.047] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 10/04/2021] [Accepted: 11/17/2021] [Indexed: 10/31/2022]
Abstract
The evolution of novel cell types has been proposed to result from duplication of gene regulatory networks, but proven examples are rare. In addition to stalk cells and spores that make up the fruiting bodies of three major groups of Dictyostelia, those in group 4 additionally evolved basal disc and cup cells that respectively anchor the stalk to the substratum and the spore mass to the stalk. We noted a putative group-4-specific duplication of a cudA-like transcription factor (TF) in a comparative analysis of group-representative genomes. Using increased taxon sampling, we here confirmed that this TF, cdl1, duplicated into cdl1a and cdl1b in the common ancestor to group 4. cdl1a, but not cdl1b, showed signatures of positive selection, indicative of functional innovation. Deletion of cdl1a in Dictyostelium discoideum resulted in fruiting bodies with sagging spore heads that lacked the supporting cup cells and expression of cup-specific genes. Deletion of cdl1b resulted in thinner fruiting body stalks, while a cdl1b-cdl1a- double knockout showed more severe stalk defects, suggesting an ancestral role of cdl1 in stalk formation. This was confirmed in a closely related non-group 4 species, Polysphondylium violaceum, where cdl1 knockout caused defective stalk formation. These data indicate that the group-specific duplication of cdl1 and subsequent diversification of cdl1a played a pivotal role in the evolution of a novel somatic cell type in group 4 Dictyostelia.
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Affiliation(s)
- Koryu Kin
- University of Dundee, School of Life Sciences, Dow Street, Dundee DD1 5EH, UK; Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain
| | - Zhi-Hui Chen
- University of Dundee, School of Life Sciences, Dow Street, Dundee DD1 5EH, UK
| | - Gillian Forbes
- University of Dundee, School of Life Sciences, Dow Street, Dundee DD1 5EH, UK
| | - Pauline Schaap
- University of Dundee, School of Life Sciences, Dow Street, Dundee DD1 5EH, UK.
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Yamada Y, Forbes G, Du Q, Kawata T, Schaap P. Loss of PIKfyve Causes Transdifferentiation of Dictyostelium Spores Into Basal Disc Cells. Front Cell Dev Biol 2021; 9:692473. [PMID: 34490246 PMCID: PMC8417116 DOI: 10.3389/fcell.2021.692473] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 07/02/2021] [Indexed: 11/13/2022] Open
Abstract
The 1-phosphatidylinositol-3-phosphate 5-kinase PIKfyve generates PtdIns3,5P2 on late phagolysosomes, which by recruiting the scission protein Atg18, results in their fragmentation in the normal course of endosome processing. Loss of PIKfyve function causes cellular hypervacuolization in eukaryotes and organ failure in humans. We identified pikfyve as the defective gene in a Dictyostelium mutant that failed to form spores. The amoebas normally differentiated into prespore cells and initiated spore coat protein synthesis in Golgi-derived prespore vesicles. However, instead of exocytosing, the prespore vesicles fused into the single vacuole that typifies the stalk and basal disc cells that support the spores. This process was accompanied by stalk wall biosynthesis, loss of spore gene expression and overexpression of ecmB, a basal disc and stalk-specific gene, but not of the stalk-specific genes DDB_G0278745 and DDB_G0277757. Transdifferentiation of prespore into stalk-like cells was previously observed in mutants that lack early autophagy genes, like atg5, atg7, and atg9. However, while autophagy mutants specifically lacked cAMP induction of prespore gene expression, pikfyve - showed normal early autophagy and prespore induction, but increased in vitro induction of ecmB. Combined, the data suggest that the Dictyostelium endosomal system influences cell fate by acting on cell type specific gene expression.
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Affiliation(s)
- Yoko Yamada
- School of Life Sciences, University of Dundee, Dundee, United Kingdom.,Department of Biology, Faculty of Science, Toho University, Funabashi, Japan.,Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, Tokyo, Japan
| | - Gillian Forbes
- School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Qingyou Du
- School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Takefumi Kawata
- Department of Biology, Faculty of Science, Toho University, Funabashi, Japan
| | - Pauline Schaap
- School of Life Sciences, University of Dundee, Dundee, United Kingdom
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Yamada Y, Schaap P. The proppin Bcas3 and its interactor KinkyA localize to the early phagophore and regulate autophagy. Autophagy 2021; 17:640-655. [PMID: 32116088 PMCID: PMC8032249 DOI: 10.1080/15548627.2020.1725403] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 01/23/2020] [Accepted: 01/29/2020] [Indexed: 11/11/2022] Open
Abstract
To resolve the signaling mechanisms that mediate the starvation-induced processes of Dictyostelium sporulation and encystation, we performed insertional mutagenesis on cells harboring an mRFP-tagged spore gene. We isolated a mutant in kinkyA (knkA), a gene without known function, which formed fruiting bodies with a kinked stalk and lacking viable spores. Immunoprecipitation of lysates of KnkA-YFP-transformed knkA- cells yielded a mammalian BCAS3 homolog as a KnkA interactor. bcas3- phenocopied knkA- and Bcas3 colocalized with KnkA to puncta. Bcas3 shares sequence similarity with proppins (beta-propellors that bind phosphoinositides). Mutation of 2 Bcas3 residues that are essential for PtdIns3P binding in proppins prevented Bcas3 binding to PtdIns3P as well as punctate Bcas3 and KnkA localization. KnkA puncta also colocalized with small but not large vesicles that contain the autophagy protein Atg8 and were contiguous with the endoplasmic reticulum. knkA- and bcas3- cells showed a pronounced decrease of RFP-GFP-Atg8 in neutral early autophagosomes, indicating that KnkA and Bcas3 are required for macroautophagy/autophagy. Knockouts in atg7, atg5 or atg9 substantiated this finding by showing similar sporulation defects as knkA- and bcas3-. Defective Dictyostelium sporulation is evidently a useful diagnostic tool for the discovery of novel autophagy genes.Abbreviations: Atg: Autophagy-related; BCAS3: BCAS3 microtubule associated cell migration factor; cAMP: 3',5'-cyclic adenosine monophosphate; ER: endoplasmic reticulum; GFP: green fluorescent protein; PAS: phagophore assembly site; PRKA/PKA: protein kinase cAMP-dependent; Proppin: beta-propellers that bind phosphoinositides; PtdIns3P: phosphatidylinositol 3-phosphate; REMI: restriction enzyme-mediated insertional mutagenesis; RFP: red fluorescent protein; RT-qPCR: reverse transcriptase - quantitative polymerase chain reaction; WIPI: WD repeat domain, phosphoinositide interacting; YFP: yellow fluorescent protein.
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Affiliation(s)
- Yoko Yamada
- School of Life Sciences, University of Dundee, Dundee, UK
- Department of Biology, Faculty of Science, Toho University, Funabashi, Japan
| | - Pauline Schaap
- School of Life Sciences, University of Dundee, Dundee, UK
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Forbes G, Chen ZH, Kin K, Lawal HM, Schilde C, Yamada Y, Schaap P. Phylogeny-wide conservation and change in developmental expression, cell-type specificity and functional domains of the transcriptional regulators of social amoebas. BMC Genomics 2019; 20:890. [PMID: 31752673 PMCID: PMC6873476 DOI: 10.1186/s12864-019-6239-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 10/29/2019] [Indexed: 11/17/2022] Open
Abstract
Background Dictyostelid social amoebas self-organize into fruiting bodies, consisting of spores and up to four supporting cell types in the phenotypically most complex taxon group 4. High quality genomes and stage- and cell-type specific transcriptomes are available for representative species of each of the four taxon groups. To understand how evolution of gene regulation in Dictyostelia contributed to evolution of phenotypic complexity, we analysed conservation and change in abundance, functional domain architecture and developmental regulation of their transcription factors (TFs). Results We detected 440 sequence-specific TFs across 33 families, of which 68% were upregulated in multicellular development and about half conserved throughout Dictyostelia. Prespore cells expressed two times more TFs than prestalk cells, but stalk cells expressed more TFs than spores, suggesting that gene expression events that define spores occur earlier than those that define stalk cells. Changes in TF developmental expression, but not in TF abundance or functional domains occurred more frequently between group 4 and groups 1–3, than between the more distant branches formed by groups 1 + 2 and 3 + 4. Conclusions Phenotypic innovation is correlated with changes in TF regulation, rather than functional domain- or TF acquisition. The function of only 34 TFs is known. Of 12 TFs essential for cell differentiation, 9 are expressed in the cell type for which they are required. The information acquired here on conserved cell type specifity of 120 additional TFs can effectively guide further functional analysis, while observed evolutionary change in TF developmental expression may highlight how genotypic change caused phenotypic innovation.
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Affiliation(s)
- Gillian Forbes
- School of Life Sciences, University of Dundee, DD15EH, Dundee, UK
| | - Zhi-Hui Chen
- School of Life Sciences, University of Dundee, DD15EH, Dundee, UK
| | - Koryu Kin
- School of Life Sciences, University of Dundee, DD15EH, Dundee, UK
| | - Hajara M Lawal
- School of Life Sciences, University of Dundee, DD15EH, Dundee, UK
| | | | - Yoko Yamada
- School of Life Sciences, University of Dundee, DD15EH, Dundee, UK
| | - Pauline Schaap
- School of Life Sciences, University of Dundee, DD15EH, Dundee, UK.
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Yamada Y, Schaap P. Cyclic AMP induction of Dictyostelium prespore gene expression requires autophagy. Dev Biol 2019; 452:114-126. [PMID: 31051160 PMCID: PMC6598861 DOI: 10.1016/j.ydbio.2019.04.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Revised: 04/06/2019] [Accepted: 04/25/2019] [Indexed: 12/27/2022]
Abstract
Dictyostelium discoideum amoebas display colonial multicellularity where starving amoebas aggregate to form migrating slugs and fruiting bodies consisting of spores and three supporting cell types. To resolve the cell signalling mechanism that control sporulation, we use insertional mutagenesis of amoebas transformed with fusion constructs of spore genes and red fluorescent protein. We identified the defective gene in a mutant lacking spore gene expression as the autophagy gene Atg7. Directed knock-out of atg7 and of autophagy genes like atg5 and atg9 yielded a similar phenotype, with lack of viable spores and excessive differentiation of stalk cells. The atg7-, atg5- and atg9- cells were specifically defective in cAMP induction of prespore genes, but showed enhanced cAMP stimulation of prestalk genes at the same developmental stage. The lack of prespore gene induction in the autophagy mutants was not due to deleterious effects of loss of autophagy on known components of the cAMP pathway, such as cAMP receptors and their cAMP-induced phosphorylation and internalization, PKA and the transcription factors SpaA and GbfA, or to lack of NH3 production by proteolysis, which was previously suggested to stimulate the spore pathway. Our continued mutagenesis approach is the most likely to yield the intriguing link between autophagy and prespore gene induction. A screen for Dictyostelium sporulation mutants identified autophagy gene atg7. Atg7-, atg5-and atg9-cells cannot form viable spores, but show normal stalk formation. Atg7-, atg5-and atg9-are specifically defective in cAMP induction of prespore genes. Atg7-, atg5-and atg9-show normal to enhanced cAMP induction of prestalk genes. PKA overexpression does not restore sporulation in autophagy mutants.
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Affiliation(s)
- Yoko Yamada
- School of Life Sciences, University of Dundee, DD15EH, Dundee, UK
| | - Pauline Schaap
- School of Life Sciences, University of Dundee, DD15EH, Dundee, UK.
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Hehmeyer J. Two potential evolutionary origins of the fruiting bodies of the dictyostelid slime moulds. Biol Rev Camb Philos Soc 2019; 94:1591-1604. [PMID: 30989827 DOI: 10.1111/brv.12516] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 03/29/2019] [Accepted: 04/01/2019] [Indexed: 11/29/2022]
Abstract
Dictyostelium discoideum and the other dictyostelid slime moulds ('social amoebae') are popular model organisms best known for their demonstration of sorocarpic development. In this process, many cells aggregate to form a multicellular unit that ultimately becomes a fruiting body bearing asexual spores. Several other unrelated microorganisms undergo comparable processes, and in some it is evident that their multicellular development evolved from the differentiation process of encystation. While it has been argued that the dictyostelid fruiting body had similar origins, it has also been proposed that dictyostelid sorocarpy evolved from the unicellular fruiting process found in other amoebozoan slime moulds. This paper reviews the developmental biology of the dictyostelids and other relevant organisms and reassesses the two hypotheses on the evolutionary origins of dictyostelid development. Recent advances in phylogeny, genetics, and genomics and transcriptomics indicate that further research is necessary to determine whether or not the fruiting bodies of the dictyostelids and their closest relatives, the myxomycetes and protosporangids, are homologous.
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Kin K, Forbes G, Cassidy A, Schaap P. Cell-type specific RNA-Seq reveals novel roles and regulatory programs for terminally differentiated Dictyostelium cells. BMC Genomics 2018; 19:764. [PMID: 30348074 PMCID: PMC6198379 DOI: 10.1186/s12864-018-5146-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 10/05/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND A major hallmark of multicellular evolution is increasing complexity by the evolution of new specialized cell types. During Dictyostelid evolution novel specialization occurred within taxon group 4. We here aim to retrace the nature and ancestry of the novel "cup" cells by comparing their transcriptome to that of other cell types. RESULTS RNA-Seq was performed on purified mature spore, stalk and cup cells and on vegetative amoebas. Clustering and phylogenetic analyses showed that cup cells were most similar to stalk cells, suggesting that they share a common ancestor. The affinity between cup and stalk cells was also evident from promoter-reporter studies of newly identified cell-type genes, which revealed late expression in cups of many stalk genes. However, GO enrichment analysis reveal the unexpected prominence of GTPase mediated signalling in cup cells, in contrast to enrichment of autophagy and cell wall synthesis related transcripts in stalk cells. Combining the cell type RNA-Seq data with developmental expression profiles revealed complex expression dynamics in each cell type as well as genes exclusively expressed during terminal differentiation. Most notable were nine related hssA-like genes that were highly and exclusively expressed in cup cells. CONCLUSIONS This study reveals the unique transcriptomes of the mature cup, stalk and spore cells of D. discoideum and provides insight into the ancestry of cup cells and roles in signalling that were not previously realized. The data presented in this study will serve as an important resource for future studies into the regulation and evolution of cell type specialization.
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Affiliation(s)
- Koryu Kin
- School of Life Sciences, University of Dundee, Angus, Dundee, DD15EH UK
| | - Gillian Forbes
- School of Life Sciences, University of Dundee, Angus, Dundee, DD15EH UK
| | - Andrew Cassidy
- Tayside Centre for Genomic Analysis, University of Dundee, Angus, Dundee, DD19SY UK
| | - Pauline Schaap
- School of Life Sciences, University of Dundee, Angus, Dundee, DD15EH UK
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