Functional Analysis of Hyaluronidase-like Genes in Ovarian Development of Macrobrachium nipponense and Comparative Evaluation with Other Key Regulatory Genes

This study conducted a bioinformatic analysis of two <i>Hyaluronidase-like</i> isoforms (<i>Mn-HyaL1</i> and <i>Mn-HyaL2</i>) in <i>Macrobrachium nipponense</i> and investigated their phylogenetic relationships. The open reading frames of <i>Mn-HyaL1</i> and <i>Mn-HyaL2</i> were 1101 bp (encoding 366 amino acids) and 1164 bp (encoding 387 amino acids), respectively. Both isoforms exhibited similar conserved domains, with an amino acid sequence similarity of 60.21%. Quantitative PCR analysis revealed that the expression levels of <i>Mn-HyaL1</i> and <i>Mn-HyaL2</i> increased during the mid-to-late phase of each developmental stage, were higher during the reproductive season than in the non-reproductive season, and were more abundant in the hepatopancreas than in other tissues. RNA interference experiments targeting both genes simultaneously demonstrated that knockdown of <i>Mn-HyaL2</i> significantly accelerated ovarian development in <i>M. nipponense</i>, indicating that <i>Mn-HyaL</i> genes function as negative regulators of ovarian maturation. A comparative analysis of multiple genes revealed the following descending order of potency in promoting ovarian development in <i>M. nipponense</i>: <i>Mn-Cholesterol 7-desaturase</i> > <i>Mn-Cathepsin L1</i>. The order of potency in inhibiting ovarian development in <i>M. nipponense</i>, from strongest to weakest, was determined to be <i>Mn-Gonad-inhibiting hormone</i> > <i>Mn-HyaL2</i>.