20 research outputs found
In silico Identification and Expression of Protocadherin Gene Family in Octopus vulgaris
No full textConnecting millions of neurons to create a functional neural circuit is a daunting challenge. Vertebrates developed a molecular system at the cell membrane to allow neurons to recognize each other by distinguishing self from non-self through homophilic protocadherin interactions. In mammals, the protocadherin gene family counts about 50 different genes. By hetero-multimerization, protocadherins are capable of generating an impressive number of molecular interfaces. Surprisingly, in the California two-spot octopus, Octopus bimaculoides, an invertebrate belonging to the Phylum Mollusca, over 160 protocadherins (PCDHs) have been identified. Here we briefly discuss the role of PCDHs in neural wiring and conduct a comparative study of the protocadherin gene family in two closely related octopus species, Octopus vulgaris and O. bimaculoides. A first glance at the expression patterns of protocadherins in O. vulgaris is also provided. Finally, we comment on PCDH evolution in the light of invertebrate nervous system plasticity
Identification of neural progenitor cells and their progeny reveals long distance migration in the developing octopus brain
No full textCephalopods have evolved nervous systems that parallel the complexity of mammalian brains in terms of neuronal numbers and richness in behavioral output. How the cephalopod brain develops has only been described at the morphological level, and it remains unclear where the progenitor cells are located and what molecular factors drive neurogenesis. Using histological techniques, we located dividing cells, neural progenitors and postmitotic neurons in Octopus vulgaris embryos. Our results indicate that an important pool of progenitors, expressing the conserved bHLH transcription factors achaete-scute or neurogenin, is located outside the central brain cords in the lateral lips adjacent to the eyes, suggesting that newly formed neurons migrate into the cords. Lineage-tracing experiments then showed that progenitors, depending on their location in the lateral lips, generate neurons for the different lobes, similar to the squid Doryteuthis pealeii. The finding that octopus newborn neurons migrate over long distances is reminiscent of vertebrate neurogenesis and suggests it might be a fundamental strategy for large brain development.sponsorship: Fonds Wetenschappelijk Onderzoek SB/1S19517N Astrid DeryckereFonds Wetenschappelijk Onderzoek SB/11D4120N Ali Murat ElagozKU Leuven ID-N/20/007 Eve SeuntjensStazione Zoologica Anton Dohrn Ruth StyfhalsKU Leuven IOFm/17/014 Gregory E Maes (Fonds Wetenschappelijk Onderzoek|SB/1S19517N, Fonds Wetenschappelijk Onderzoek|SB/11D4120N, KU Leuven|N/20/007, KU Leuven|IOFm/17/014, Stazione Zoologica Anton Dohrn)status: Publishe
MicroRNAs are deeply linked to the emergence of the complex octopus brain
No full textSoft-bodied cephalopods such as octopuses are exceptionally intelligent invertebrates with a highly complex nervous system that evolved independently from vertebrates. Because of elevated RNA editing in their nervous tissues, we hypothesized that RNA regulation may play a major role in the cognitive success of this group. We thus profiled messenger RNAs and small RNAs in three cephalopod species including 18 tissues of the Octopus vulgaris. We show that the major RNA innovation of soft-bodied cephalopods is an expansion of the microRNA (miRNA) gene repertoire. These evolutionarily novel miRNAs were primarily expressed in adult neuronal tissues and during the development and had conserved and thus likely functional target sites. The only comparable miRNA expansions happened, notably, in vertebrates. Thus, we propose that miRNAs are intimately linked to the evolution of complex animal brains
The survey and reference assisted assembly of the Octopus vulgaris genome
No full textThe common octopus, Octopus vulgaris, is an active marine predator known for the richness and
plasticity of its behavioral repertoire, and remarkable learning and memory capabilities. Octopus
and other coleoid cephalopods, cuttlefish and squid, possess the largest nervous system among
invertebrates, both for cell counts and body to brain size. O. vulgaris has been at the center of a longtradition
of research into diverse aspects of its biology. To leverage research in this iconic species, we
generated 270 Gb of genomic sequencing data, complementing those available for the only other
sequenced congeneric octopus, Octopus bimaculoides. We show that both genomes are similar in size,
but display different levels of heterozygosity and repeats. Our data give a first quantitative glimpse into
the rate of coding and non-coding regions and support the view that hundreds of novel genes may have
arisen independently despite the close phylogenetic distance. We furthermore describe a referenceguided
assembly and an open genomic resource (CephRes-gdatabase), opening new avenues in the
study of genomic novelties in cephalopods and their biology.sponsorship: We are recognizing the contribution of Drs A. Cole (currently at University of Vienna), N. Tublitz (Oregon University), and C. Di Cristo (University of Sannio and CephRes) for their generous support at an earlier stage of this project. The contribution of the State Key Laboratory of Agricultural Genomics (grant No. 2011DQ782025) to GEM is also appreciated. EAR and OS are supported by a grant from the Austrian Science Fund (FWF): P30686-B29. We thank the COST Action (FA1301) that facilitated the networking initiative underlying this study. Genome browsers are integrated in the CephRes databases-website platform (http://www.cephalopodresearch.org/ceph_gdatab/) based on a bilateral agreement with University of Vienna. This study was supported by BGIShenzhen and by the Association for Cephalopod Research 'CephRes' a no-profit organization. (State Key Laboratory of Agricultural Genomics|2011DQ782025, Austrian Science Fund (FWF)|P30686-B29, COST Action|FA1301, BGIShenzhen, Association for Cephalopod Research 'CephRes' a no-profit organization, Austrian Science Fund (FWF)|P30686)status: Published onlin
Data_Sheet_1_In silico Identification and Expression of Protocadherin Gene Family in Octopus vulgaris.pdf
No full textConnecting millions of neurons to create a functional neural circuit is a daunting challenge. Vertebrates developed a molecular system at the cell membrane to allow neurons to recognize each other by distinguishing self from non-self through homophilic protocadherin interactions. In mammals, the protocadherin gene family counts about 50 different genes. By hetero-multimerization, protocadherins are capable of generating an impressive number of molecular interfaces. Surprisingly, in the California two-spot octopus, Octopus bimaculoides, an invertebrate belonging to the Phylum Mollusca, over 160 protocadherins (PCDHs) have been identified. Here we briefly discuss the role of PCDHs in neural wiring and conduct a comparative study of the protocadherin gene family in two closely related octopus species, Octopus vulgaris and O. bimaculoides. A first glance at the expression patterns of protocadherins in O. vulgaris is also provided. Finally, we comment on PCDH evolution in the light of invertebrate nervous system plasticity.</p
A practical staging atlas to study embryonic development of Octopus vulgaris under controlled laboratory conditions
No full textBackground Octopus vulgaris has been an iconic cephalopod species for neurobiology research as well as for cephalopod aquaculture. It is one of the most intelligent and well-studied invertebrates, possessing both long- and short-term memory and the striking ability to perform complex cognitive tasks. Nevertheless, how the common octopus developed these uncommon features remains enigmatic. O. vulgaris females spawn thousands of small eggs and remain with their clutch during their entire development, cleaning, venting and protecting the eggs. In fact, eggs incubated without females usually do not develop normally, mainly due to biological contamination (fungi, bacteria, etc.). This high level of parental care might have hampered laboratory research on the embryonic development of this intriguing cephalopod. Results Here, we present a completely parameter-controlled artificial seawater standalone egg incubation system that replaces maternal care and allows successful embryonic development of a small-egged octopus species until hatching in a laboratory environment. We also provide a practical and detailed 1 staging atlas based on bright-field and light sheet fluorescence microscopy imaging for precise monitoring of embryonic development. The atlas has a comparative section to benchmark stages to the different scales published by Naef (1928), Arnold (1965) and Boletzky (2016). Finally, we provide methods to monitor health and wellbeing of embryos during organogenesis. Conclusion Besides introducing the study of O. vulgaris embryonic development to a wider community, this work can be a high-quality reference for comparative evolutionary developmental biology
Video6_Optimization of Whole Mount RNA Multiplexed in situ Hybridization Chain Reaction With Immunohistochemistry, Clearing and Imaging to Visualize Octopus Embryonic Neurogenesis.MP4
No full textGene expression analysis has been instrumental to understand the function of key factors during embryonic development of many species. Marker analysis is also used as a tool to investigate organ functioning and disease progression. As these processes happen in three dimensions, the development of technologies that enable detection of gene expression in the whole organ or embryo is essential. Here, we describe an optimized protocol of whole mount multiplexed RNA in situ hybridization chain reaction version 3.0 (HCR v3.0) in combination with immunohistochemistry (IHC), followed by fructose-glycerol clearing and light sheet fluorescence microscopy (LSFM) imaging on Octopus vulgaris embryos. We developed a code to automate probe design which can be applied for designing HCR v3.0 type probe pairs for fluorescent in situ mRNA visualization. As proof of concept, neuronal (Ov-elav) and glial (Ov-apolpp) markers were used for multiplexed HCR v3.0. Neural progenitor (Ov-ascl1) and precursor (Ov-neuroD) markers were combined with immunostaining for phosphorylated-histone H3, a marker for mitosis. After comparing several tissue clearing methods, fructose-glycerol clearing was found optimal in preserving the fluorescent signal of HCR v3.0. The expression that was observed in whole mount octopus embryos matched with the previous expression data gathered from paraffin-embedded transverse sections. Three-dimensional reconstruction revealed additional spatial organization that had not been discovered using two-dimensional methods.</p
DataSheet1_Optimization of Whole Mount RNA Multiplexed in situ Hybridization Chain Reaction With Immunohistochemistry, Clearing and Imaging to Visualize Octopus Embryonic Neurogenesis.docx
No full textGene expression analysis has been instrumental to understand the function of key factors during embryonic development of many species. Marker analysis is also used as a tool to investigate organ functioning and disease progression. As these processes happen in three dimensions, the development of technologies that enable detection of gene expression in the whole organ or embryo is essential. Here, we describe an optimized protocol of whole mount multiplexed RNA in situ hybridization chain reaction version 3.0 (HCR v3.0) in combination with immunohistochemistry (IHC), followed by fructose-glycerol clearing and light sheet fluorescence microscopy (LSFM) imaging on Octopus vulgaris embryos. We developed a code to automate probe design which can be applied for designing HCR v3.0 type probe pairs for fluorescent in situ mRNA visualization. As proof of concept, neuronal (Ov-elav) and glial (Ov-apolpp) markers were used for multiplexed HCR v3.0. Neural progenitor (Ov-ascl1) and precursor (Ov-neuroD) markers were combined with immunostaining for phosphorylated-histone H3, a marker for mitosis. After comparing several tissue clearing methods, fructose-glycerol clearing was found optimal in preserving the fluorescent signal of HCR v3.0. The expression that was observed in whole mount octopus embryos matched with the previous expression data gathered from paraffin-embedded transverse sections. Three-dimensional reconstruction revealed additional spatial organization that had not been discovered using two-dimensional methods.</p
Additional file 14 of A practical staging atlas to study embryonic development of Octopus vulgaris under controlled laboratory conditions
No full textAdditional file 14. Movie of external yolk contraction at Stage XI. The yolk sack of the embryo contracts between Stages IX and XVI and is shown here at Stage XI
Table1_Optimization of Whole Mount RNA Multiplexed in situ Hybridization Chain Reaction With Immunohistochemistry, Clearing and Imaging to Visualize Octopus Embryonic Neurogenesis.DOCX
No full textGene expression analysis has been instrumental to understand the function of key factors during embryonic development of many species. Marker analysis is also used as a tool to investigate organ functioning and disease progression. As these processes happen in three dimensions, the development of technologies that enable detection of gene expression in the whole organ or embryo is essential. Here, we describe an optimized protocol of whole mount multiplexed RNA in situ hybridization chain reaction version 3.0 (HCR v3.0) in combination with immunohistochemistry (IHC), followed by fructose-glycerol clearing and light sheet fluorescence microscopy (LSFM) imaging on Octopus vulgaris embryos. We developed a code to automate probe design which can be applied for designing HCR v3.0 type probe pairs for fluorescent in situ mRNA visualization. As proof of concept, neuronal (Ov-elav) and glial (Ov-apolpp) markers were used for multiplexed HCR v3.0. Neural progenitor (Ov-ascl1) and precursor (Ov-neuroD) markers were combined with immunostaining for phosphorylated-histone H3, a marker for mitosis. After comparing several tissue clearing methods, fructose-glycerol clearing was found optimal in preserving the fluorescent signal of HCR v3.0. The expression that was observed in whole mount octopus embryos matched with the previous expression data gathered from paraffin-embedded transverse sections. Three-dimensional reconstruction revealed additional spatial organization that had not been discovered using two-dimensional methods.</p
