title: Follicle cell trypsin-like protease HrOvochymase: Its cDNA cloning, localization, and involvement in the late stage of oogenesis in the ascidian Halocynthia roretzi.
abstract: We previously reported that the sperm trypsin-like protease HrAcrosin and its precursor HrProacrosin participate in fertilization of the ascidian Halocynthia roretzi. The HrProacrosin gene is annotated in the H. roretzi genome database as Harore.CG.MTP2014.S89.g15383; our previously reported sequence of HrProacrosin gene appeared to include four nucleotides inserted near the 3'-end of HrProacrosin, resulting in a frame-shift mutation and a premature termination codon. The gene architecture of HrProacrosin and Harore.CG.MTP2014.S89.g15383 resembles that of Xenopus laevis ovochymase-1/OVCH1 and ovochymase-2/OVCH2, which encode egg extracellular polyproteases. Considering these new observations, we evaluated the cDNA cloning, expression, localization, and function of Harore.CG.MTP2014.S89.g15383, herein designated as HrOvochymase/HrOVCH. We found that HrOVCH cDNA consists of a single open reading frame of 1,575 amino acids, containing a signal peptide, three trypsin-like protease domains, and six CUB domains. HrOVCH was transcribed by the testis and ovary, but the majority of protein exists in ovarian follicle cells surrounding eggs. An anti-HrOVCH antibody inhibited elevation of the vitelline coat at a late stage of oogenesis, during the period when self-sterility is acquired. As trypsin inhibitors are reported to block the acquisition of self-sterility during oogenesis, whereas trypsin induces the acquisition of self-sterility and elevation of the vitelline coat in defolliculated ovarian eggs, we propose that HrOVCH may play a role in the acquisition of self-sterility by late-stage H. roretzi oocytes.
authors.affiliation: Sugashima Marine Biological Laboratory, Graduate School of Science, Nagoya University, Sugashima, Toba, Japan.
authors.forename: Masako
authors.initials: M
authors.lastname: Mino
authors.affiliation: Sugashima Marine Biological Laboratory, Graduate School of Science, Nagoya University, Sugashima, Toba, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Sawada
mesh_terms: D000818:Animals; D003001:Cloning, Molecular; D018076:DNA, Complementary; D010450:Endopeptidases / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D005306:Fertilization; D009866:Oogenesis; D014561:Urochordata / Q000166:cytology / Q000201:enzymology* / Q000235:genetics
chemical_list: D018076:DNA, Complementary; D010450:Endopeptidases; C092314:ovochymase