Gonadal somatic cell-specific transforming growth factor-β superfamily member in the Yesso scallop reveals gonadal somatic cell distribution during the reproductive phase

• Published in: Gene 2021-06, Vol.787, p.145627-145627, Article 145627
• Main Authors: Konuma, Mizuki, Nagasawa, Kazue, Mokrina, Mariia, Kobayashi, Mutsuko, Osada, Makoto
• Format: Article
• Language: English
• Subjects: Animals; Antigens, Differentiation; Bivalve; Bone Morphogenetic Proteins - genetics; Bone Morphogenetic Proteins - metabolism; Computer Simulation; Female; Genetic Markers; Germinal acini; Gonads - cytology; Gonads - growth & development; Gonads - metabolism; In Situ Hybridization; Leydig cells; Male; Mollusc; Pectinidae - cytology; Pectinidae - genetics; Pectinidae - growth & development; Pectinidae - metabolism; Phylogeny; Real-Time Polymerase Chain Reaction; Reproduction; RNA, Messenger - metabolism; Sertoli cells; Signal Transduction; TGF-beta Superfamily Proteins - genetics; TGF-beta Superfamily Proteins - metabolism; Tissue Distribution; Transcriptome
• ISSN: 0378-1119; 1879-0038
• DOI: 10.1016/j.gene.2021.145627

•This study identified 11 TGFβ-related genes in the Yesso scallop.•bmp2a and bmp10a mRNAs were specifically expressed in gonads.•bmp2a mRNA signal was specifically observed in the gonadal somatic cells.•bmp2a mRNA level increased in gonads of both sexes during the reproductive phase.•Gonadal somatic cell distribution was visualized in the Yesso scallop. The objective of this study was to identify the gonadal somatic cells in the Yesso scallop using a novel molecular marker. This study is the first to identify the bone morphogenetic protein 2a (Bmp2a) gene as a gonadal somatic cell-specific gene in this bivalve. We performed a transcriptomic survey to identify the transforming growth factor-β (TGFβ) superfamily members that act in Yesso scallop gonad development. BLAST survey, phylogenetic tree, and RT-PCR analyses screened BMP molecules (i.e., bmp2a and bmp10a), which are members of the TGFβ superfamily that show gonad-specific expression. Among the BMPs from the Yesso scallop, in situ hybridization accompanied by RNAscope assay identified that bmp2a mRNA was specifically expressed in the gonadal somatic cells localized in the interspace between germ cells. Real-time quantitative PCR (qPCR) analysis revealed that bmp2a mRNA expression increased during the reproductive phase. The relative expression of bmp2a mRNA was lowest at the beginning of the growing stage and peaked at the mature stage in both sexes. These observations indicate that bmp2a-positive gonadal somatic cells support germ cell growth and differentiation during the reproductive phase for both sexes. This study provides new insights into gonadal somatic cell biology in marine invertebrates and we propose that TGFβ signaling is necessary for gonad development in bivalves.