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Our Tentacley Friends 9/30/12 Does tentacle gene expression explain the novel life cycle of the parasic sea anemone Edwardsiella lineata Venus Fung Caitlin Russell hp://www.marlin.ac.uk/imgs/o_edwcar.jpg Our Tentacley Friends Corallimorph – Ricordea florida Acropora millepora 1 9/30/12 Our Tentacley Friends Nematostella vectensis Be more direct than saying “ Ed is an interesng Cnidarian.” Make clear that it will be the focus of your studies. And be clear that it is very closely Edwardsiella lineata related to Nematostella, which is arguably the leading cnidarian model system. Lifecycle of Edwardsiella larva comb jelly parasites larva 2 9/30/12 polyp parasite No tentacles Tentacles present host present host absent larva Cnidarian Tentacles • Cnidarian means “snging creatures” • Adult polyps typically have tentacles with sngers (nematocytes) for predaon • Number and length varies with species • Tentacles start to develop in oral end during polyp stage, mostly surrounding the pharynx hp://w3.shorecrest.org/~Lisa_Peck/MarineBio/syllabus/ hp://content62.eol.org/content/2010/03/30/04/95792_580_360.jpg ch7invertebrates/Invertwp/2007/eby/realseaanemone.JPG 3 9/30/12 (Marlow et al., 2008) Select genes expressed in polyp stage of Nematostella development Quesons • Do the same genes control tentacle cell differenaon and development in mulple cnidarians with diverse tentacle arrangements? • What can the mulple life stages of Edwardsiella tell us about these genes’ mes of expression? State the hypothesis explicitly, that tentacle gene expression will be suppressed in the Edwardsiella parasite relave to the polyp. 4 9/30/12 (Marlow et al., 2008) Select genes expressed in polyp stage of Nematostella development Our Approach • Focused on 3 genes from different families that are known to exhibit tentacle-specific expression in the model cnidarian Nematostella vectensis. • For each gene: – Obtained Nematostella protein sequence through NCBI – Performed BLAST searches of transcriptomic data sets to find orthologous sequences in other cnidarians – Verified orthology of newly idenfied genes through mof analysis, phylogenic analysis, and reciprocal BLAST searches. – Compared expression levels of “tentacle genes” in Edwardsiella throughout different life stages 5 9/30/12 Mef2 (Myocyte Enhancer Factor 2) In-situ hybridizaon of Nv-mef2 (Marndale et al., 2004) Mef2 Gene • Myocyte enhancer factor 2 is present in mulple organisms and has mulple funcons • A cnidarian Mef2 homologue (PcMef2) was first reported in the hydrozoan Podocoryne carnea (Spring et al.,2002) • Expressed endodermally in Podocoryne, but is expressed in both ectoderm and endoderm in Nematostella – Endoderm: downregulang cell proliferaon aer gastrulaon – Ectoderm: Neuron differenaon 6 9/30/12 Mef2 mofs Nematostella Edwardsiella Corallimorph Acropora Xenopus (clawed frog) Humans Raus (Norway rat) •Mef2 genes from cnidarians and vertebrates found to share 5-6 conserved mofs. •Frog, Rat, and Human mef2 genes closely related because they are a splice variant mef2A and code for muscle differenaon Mef2 mofs Nematostella Edwardsiella Corallimorph Acropora Xenopus (clawed frog) Humans Raus (Norway rat) •Mofs 12 and 13 are specific to cnidarians 7 9/30/12 levels of Mef2 expression 4000 3493 3500 3000 2718 2547 2500 2059 1982 2000 1500 Number of Raw Reads 1000 500 0 Parasite Parasite -> Planula Planula Planula -> Adult Adult Life Stages of Edwardsiella lineata • Mef2 expressed most during planula to adult stage; possibly nematocyte development? • Tentacle development is suppressed during parasite stage, so would have expected low level. levels of Mef2 expression 4000 3493 3500 3000 2718 2547 2500 2059 1982 2000 1500 Number of Raw Reads 1000 500 0 Parasite Parasite -> Planula Planula Planula -> Adult Adult Life Stages of Edwardsiella lineata • Compared to average of all the raw read counts of different genes on different life cyles of Ed, 712.1060671, overall high numbers across all life stages because it is involved in neuron differenaon and maintenance 8 9/30/12 FGFRb Fibroblast Growth Factor Receptor b In-situ hybridizaon of Nv-FGFRb (Matus et al., 2007) About the FGF Family • One of the receptors for the fibroblast growth factor family – Coordinates gastrulaon movements (Matus et al., 2007) and is involved in a wide variety of developmental processes in vertebrates and invertebrates (Borland et al., 2001; Bocher and Niehrs, 2005; Huang and Stern, 2005; Thisse and Thisse, 2005) • FGFRs facilitate signaling from FGFs by binding to them • NvFGFRb is expressed orally and aborally during development (Matus et al., 2007) • First appears in planula stage of Nematostella development • Highly, but not exclusively expressed in tentacles. 9 9/30/12 Comparing FGFRb and FGFRa Nematostella Edwardsiella Saccoglossus (Acorn worm) Nematostella Ra Edwardsiella Ra •Both Rb and Ra contain similar funconal domains Comparing FGFRb and FGFRa Nematostella Edwardsiella Saccoglossus (Acorn worm) Nematostella Ra Edwardsiella Ra •Many overlaps because FGFRb is expressed in apical tu before expression in tentacles •FGFRa is expressed in aboral ectoderm during development 10 9/30/12 NvFGFRa v. NvFGFRb NvFGFRa v. NvFGFRb •What makes them different: Rb is expressed in tentacles and inter-tentacle endoderm during later polyp development 11 9/30/12 FGFRb Phylogenec Tree 100 98 50 67 • Compared Rb and Ra genes of Ed and Nem to those of acorn worm and clawed frog to see their resemblence • As expected, Rb genes for Ed and Nem are more closely related to each other than they are to their respecve Ra genes • Suggests cnidarian specific FGFs – corresponds to results from Matus et al., (2007) stang that Nem FGFs fail to group with other Bilaterian FGFs in a phylogenec analysis levels of FGFRb expression 8000 7435 7000 6000 5193 5000 4287 3956 4000 3000 1882 Number of Raw Reads 2000 1000 0 Parasite Parasite -> Planula Planula Planula -> Adult Adult Life Stages of Edwardsiella lineata • FGFRb responsible for mulple endodermal areas (pharynx, mesenteries, apical tu) during planula stage • Highly expressed in all areas besides parasite because FGF regulates gastrulaon and cell differenaon 12 9/30/12 Cnidarian Specific? Nematostella Edwardsiella It may not be possible to associate any parcular region of the protein with tentacle development. It may be that the key is that this protein must be expressed in the right place at the right me if it is to contribute to tentacle development. When and where the protein is Saccoglossus expressed has nothing to do necessarily with the protein sequence itself, but more with the (Acorn worm) upstream transcripon factors that control its expression or the regulatory sequences of the FGFRa gene. Nematostella Ra Edwardsiella Ra •Then asked which regions are only present in cnidarians, which might narrow down which regions are responsible for tentacle development •Saccoglossus kowalevskii (Acorn worm) Rb gene used to compare Cnidarian Specific? Nematostella Edwardsiella Saccoglossus (Acorn worm) Nematostella Ra Edwardsiella Ra •Based on graph of expression in Ed life stages, we can’t conclude that this mof codes for tentacles •They could also just be congs specific to cnidarians •Future research needed to determine funcon of mof 9 13 9/30/12 PaxA What is a Pax gene? • “Paired box (Pax) genes are a family of ssue specific transcripon factors containing a paired domain and usually a paral or complete homeodomain. An octapepde may also be present. Pax proteins are important in early animal development for the specificaon of specific ssues, as well as during epimorphic limb regeneraon in animals capable of such.” (hp://en.wikipedia.org/wiki/Pax_genes) 14 9/30/12 What is a Pax gene? • 4 classes of Pax genes in cnidarians • Involved with development of central nervous system and sensory organs; might have a role in tentacle formaon • In Cnidaria, Pax genes were first idenfied in Acropora millepora (Miller et al., 2000) and then in Nematostella vectensis (Matus et al., 2007) Conserved mofs in Cnidarian Pax Proteins NvPaxA NvPaxB NvPaxC NvPaxD ApPaxA ApPaxB ApPaxC ApPaxD EdPaxA CmPax • looked like we only had part of the EdPax gene, but it did look similar to the other PaxA genes • What we though was the Corallimorph PaxA gene actually looks more like the PaxB genes 15 9/30/12 Conserved mofs in Cnidarian Pax Proteins NvPaxA NvPaxB NvPaxC NvPaxD ApPaxA ApPaxB ApPaxC ApPaxD EdPaxA CmPax • looked like we only had part of the EdPax gene, but it did look similar to the other PaxA genes • What we though was the Corallimorph PaxA gene actually looks more like the PaxD genes Problem Solving! • Went back to Edbase and looked at other results • Also ran a BLAST against raw reads– came up with nothing • Ran against congs database– came up with a match 16 9/30/12 Conserved mofs in Cnidarian Pax Proteins NvPaxA NvPaxB NvPaxC NvPaxD ApPaxA ApPaxB ApPaxC ApPaxD EdPaxA EdPaxA.1 CmPax EdPaxCong NvPaxA NvPaxB NvPaxC NvPaxD ApPaxA ApPaxB ApPaxC ApPaxD EdPaxA EdPaxA.1 CmPax EdPaxCong 17 9/30/12 Conserved mofs in Cnidarian Pax Proteins NvPaxA NvPaxB NvPaxC NvPaxD ApPaxA ApPaxB ApPaxC ApPaxD EdPaxA EdPaxA.1 CmPax EdPaxCong • looks like we have another possible part of EdPaxA Conserved mofs in Cnidarian Pax Proteins NvPaxA NvPaxB NvPaxC NvPaxD ApPaxA ApPaxB ApPaxC ApPaxD EdPaxA EdPaxA.1 CmPax EdPaxCong • looks like we have another possible part of EdPaxA 18 9/30/12 Mof Analysis NvPaxA NvPaxB NvPaxC NvPaxD ApPaxA ApPaxB ApPaxC ApPaxD EdPaxA EdPaxA.1 CmPax EdPaxCong • looks like we have another possible part of EdPaxA • Cong result looks more like the PaxBs Mof Analysis NvPaxA
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