AUTHOR=Kawada Tsuyoshi , Shiraishi Akira , Matsubara Shin , Hozumi Akiko , Horie Takeo , Sasakura Yasunori , Satake Honoo 

TITLE=Vasopressin Promoter Transgenic and Vasopressin Gene-Edited Ascidian, Ciona intestinalis Type A (Ciona robusta): Innervation, Gene Expression Profiles, and Phenotypes

JOURNAL=Frontiers in Endocrinology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2021.668564

DOI=10.3389/fendo.2021.668564

ISSN=1664-2392

ABSTRACT=<p>Oxytocin (OT) and vasopressin (VP) superfamily neuropeptides are distributed in not only vertebrates but also diverse invertebrates. However, no VPergic innervation of invertebrates has ever been documented. In the ascidian, <italic>Ciona intestinalis</italic> Type A (<italic>Ciona robusta</italic>), an OT/VP superfamily peptide was identified, and the <italic>Ciona</italic> vasopressin (CiVP) induces oocyte maturation and ovulation. In the present study, we characterize the innervation and phenotypes of genetically modified <italic>Ciona</italic>: <italic>CiVP</italic> promoter-Venus transgenic and <italic>CiVP</italic> mutants. <italic>CiVP</italic> promoter-Venus transgenic <italic>Ciona</italic> demonstrated that <italic>CiVP</italic> gene was highly expressed in the cerebral ganglion and several nerves. Fluorescence was also detected in the ovary of young <italic>CiVP</italic> promoter-Venus transgenic ascidians, suggesting that the <italic>CiVP</italic> gene is also expressed temporarily in the ovary of young ascidians. Furthermore, a marked decrease of post-vitellogenic (stage III) follicles was observed in the ovary of <italic>CiVP</italic> mutants, whereas pre-vitellogenic (stage I) and vitellogenic (stage II) follicles were increased in the mutant ovary, compared with that of wildtype <italic>Ciona</italic>. Gene expression profiles showed that the expression of various genes, including genes related to ovarian follicle growth, was altered in the ovary of <italic>CiVP</italic> mutants. Altogether, these results indicated that CiVP, mainly as a neuropeptide, plays pivotal roles in diverse biological functions, including growth of early-stage ovarian follicles <italic>via</italic> regulation of the expression of a wide variety of genes. This is the first report describing a <italic>VP</italic> gene promoter-transgenic and <italic>VP</italic> gene-edited invertebrate and also on its gene expression profiles and phenotypes.</p>