AUTHOR=Wahl Melody , Levy Tom , Manor Rivka , Aflalo Eliahu D. , Sagi Amir , Aizen Joseph 

TITLE=Genes Encoding the Glycoprotein Hormone GPA2/GPB5 and the Receptor LGR1 in a Female Prawn

JOURNAL=Frontiers in Endocrinology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2022.823818

DOI=10.3389/fendo.2022.823818

ISSN=1664-2392

ABSTRACT=<p>In vertebrate reproduction, metabolism, growth and development, essential roles are played by glycoprotein hormones, such as follicle-stimulating hormone (FSH), luteinizing hormone (LH) and thyroid-stimulating hormone (TSH), all of which are heterodimers consisting of two subunits, a structurally identical alpha subunit, and a variable beta subunit, which provides specificity. A 'new' glycoprotein hormone heterodimer identified in both vertebrates and invertebrates, including decapod crustaceans, was shown to be composed of the glycoprotein alpha 2 (GPA2) and glycoprotein beta 5 (GPB5) subunits. The putative receptor for GPA2/GPB5 in invertebrates is the leucine-rich repeat-containing G protein-coupled receptor 1 (LGR1). In this study in the giant freshwater prawn, <italic>Macrobrachium rosenbergii</italic>, we identified and characterized the GPA2 <italic>(MrGPA2)</italic>, GPB5 <italic>(MrGPB5)</italic> and LGR1 <italic>(MrLGR1)</italic> encoding genes and revealed their spatial expression patterns in female animals. Loss-of-function RNA interference (RNAi) experiments in <italic>M. rosenbergii</italic> females demonstrated a negative correlation between <italic>MrGPA2/MrGPB5</italic> silencing and <italic>MrLGR1</italic> transcript levels, suggesting a possible ligand–receptor interaction. The relative transcript levels of <italic>M. rosenbergii</italic> vitellogenin <italic>(MrVg)</italic> in the hepatopancreas were significantly reduced following <italic>MrGPA2/MrGPB5</italic> knockdown. <italic>MrLGR1</italic> loss-of-function induced MrVg receptor <italic>(MrVgR)</italic> transcript levels in the ovary and resulted in significantly larger oocytes in the silenced group compared to the control group. Our results provide insight into the possible role of GPA2/GPB5-LGR1 in female reproduction, as shown by its effect on <italic>MrVg</italic> and <italic>MrVgR</italic> expression and on the oocyte development. Here, we suggest that the GPA2/GPB5 heterodimer act as a gonad inhibiting factor in the eyestalk-hepatopancreas-ovary endocrine axis in <italic>M. rosenbergii</italic>.</p>