RRC ID 58574
Author Tajima Y, Hozumi A, Yoshida K, Treen N, Sakuma T, Yamamoto T, Sasakura Y.
Title Hox13 is essential for formation of a sensory organ at the terminal end of the sperm duct in Ciona.
Journal Dev Biol
Abstract Species-specific traits are thought to have been acquired by natural selection. Transcription factors play central roles in the evolution of species-specific traits. Hox genes encode a set of conserved transcription factors essential for establishing the anterior-posterior body axis of animals. Changes in the expression or function of Hox genes can lead to the diversification of animal-body plans. The tunicate ascidian Ciona intestinalis Type A has an orange-colored structure at the sperm duct terminus. This orange-pigmented organ (OPO) is the characteristic that can distinguish this ascidian from other closely related species. The OPO is formed by the accumulation of orange-pigmented cells (OPCs) that are present throughout the adult body. We show that Hox13 is essential for formation of the OPO. Hox13 is expressed in the epithelium of the sperm duct and neurons surrounding the terminal openings for sperm ejection, while OPCs themselves do not express this gene. OPCs are mobile cells that can move through the body vasculature by pseudopodia, suggesting that the OPO is formed by the accumulation of OPCs guided by Hox13-positive cells. Another ascidian species, Ciona savignyi, does not have an OPO. Like Hox13 of C. intestinalis, Hox13 of C. savignyi is expressed at the terminus of its sperm duct; however, its expression domain is limited to the circular area around the openings. The genetic changes responsible for the acquisition or loss of OPO are likely to occur in the expression pattern of Hox13.
Volume 458(1)
Pages 120-131
Published 2020-2-1
DOI 10.1016/j.ydbio.2019.10.028
PII S0012-1606(19)30270-2
PMID 31682808
MeSH Animals Ciona / genetics Ciona / growth & development Ciona intestinalis / genetics* Ciona intestinalis / growth & development Epithelial Cells / metabolism Gene Expression Regulation, Developmental* Genes, Homeobox Genitalia, Male / cytology Genitalia, Male / growth & development* Male Models, Biological Neurons / metabolism Pigments, Biological Sense Organs / growth & development* Species Specificity
IF 2.896
Times Cited 0
C.intestinalis / (O.japonicus) pMiCiHox13>Kaede pSPCiHox13>Kaede Tg[MiCiHox13K]1 Tg[MiCiHox13K]2 pHTB-TALEN-NG::2A::mCherry pEF1a>TALEN-NG::2A::mCherry pAKR>TALEN-NG::2A::mCherry pCesA>TALEN-NG::2A::mCherry pNut>TALEN-NG::2A::mCherry pTnI>TALEN-NG::2A::mCherry Wild C. int