Publications by authors named "Sawa Iwasaki-Yokozawa"

3 Publications

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Experimental duplication of bilaterian body axes in spider embryos: Holm's organizer and self-regulation of embryonic fields.

Dev Genes Evol 2020 03 10;230(2):49-63. Epub 2019 Apr 10.

Laboratory of Evolutionary Cell and Developmental Biology, JT Biohistory Research Hall, 1-1 Murasaki-cho, Takatsuki, Osaka, 569-1125, Japan.

Bilaterally symmetric body plans of vertebrates and arthropods are defined by a single set of two orthogonal axes, the anterior-posterior (or head-tail) and dorsal-ventral axes. In vertebrates, and especially amphibians, complete or partial doubling of the bilaterian body axes can be induced by two different types of embryological manipulations: transplantation of an organizer region or bi-sectioning of an embryo. Such axis doubling relies on the ability of embryonic fields to flexibly respond to the situation and self-regulate toward forming a whole body. This phenomenon has facilitated experimental efforts to investigate the mechanisms of vertebrate body axes formation. However, few studies have addressed the self-regulatory capabilities of embryonic fields associated with body axes formation in non-vertebrate bilaterians. The pioneer spider embryologist Åke Holm reported twinning of spider embryos induced by both types of embryological manipulations in 1952; yet, his experiments have not been replicated by other investigators, and access to spider or non-vertebrate twins has been limited. In this review, we provide a historical background on twinning experiments in spiders, and an overview of current twinning approaches in familiar spider species and related molecular studies. Moreover, we discuss the benefits of the spider model system for a deeper understanding of the ancestral mechanisms of body axes formation in arthropods, as well as in bilaterians.
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http://dx.doi.org/10.1007/s00427-019-00631-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7128006PMC
March 2020

Homeobox Gene Duplication and Divergence in Arachnids.

Mol Biol Evol 2018 09;35(9):2240-2253

Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, United Kingdom.

Homeobox genes are key toolkit genes that regulate the development of metazoans and changes in their regulation and copy number have contributed to the evolution of phenotypic diversity. We recently identified a whole genome duplication (WGD) event that occurred in an ancestor of spiders and scorpions (Arachnopulmonata), and that many homeobox genes, including two Hox clusters, appear to have been retained in arachnopulmonates. To better understand the consequences of this ancient WGD and the evolution of arachnid homeobox genes, we have characterized and compared the homeobox repertoires in a range of arachnids. We found that many families and clusters of these genes are duplicated in all studied arachnopulmonates (Parasteatoda tepidariorum, Pholcus phalangioides, Centruroides sculpturatus, and Mesobuthus martensii) compared with nonarachnopulmonate arachnids (Phalangium opilio, Neobisium carcinoides, Hesperochernes sp., and Ixodes scapularis). To assess divergence in the roles of homeobox ohnologs, we analyzed the expression of P. tepidariorum homeobox genes during embryogenesis and found pervasive changes in the level and timing of their expression. Furthermore, we compared the spatial expression of a subset of P. tepidariorum ohnologs with their single copy orthologs in P. opilio embryos. We found evidence for likely subfunctionlization and neofunctionalization of these genes in the spider. Overall our results show a high level of retention of homeobox genes in spiders and scorpions post-WGD, which is likely to have made a major contribution to their developmental evolution and diversification through pervasive subfunctionlization and neofunctionalization, and paralleling the outcomes of WGD in vertebrates.
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http://dx.doi.org/10.1093/molbev/msy125DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6107062PMC
September 2018

Genome-scale embryonic developmental profile of gene expression in the common house spider .

Data Brief 2018 Aug 24;19:865-867. Epub 2018 May 24.

Laboratory of Evolutionary Cell and Developmental Biology, JT Biohistory Research Hall, 1-1 Murasaki-cho, Takatsuki, Osaka 569-1125, Japan.

We performed RNA sequencing (RNA-Seq) at ten successive developmental stages in embryos of the common house spider . Two independent datasets from two pairs of parents represent the normalized coverage of mapped RNA-Seq reads along scaffolds of the genome assembly. Transcript abundance was calculated against existing AUGUSTUS gene models. The datasets have been deposited in the Gene Expression Omnibus (GEO) Database at the National Center for Biotechnology Information (NCBI) under the accession number GSE112712.
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http://dx.doi.org/10.1016/j.dib.2018.05.106DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5997937PMC
August 2018