Integrated Genomic and Transcriptomic Analysis Reveals a Transcription Factor Gene Set Facilitating Gonadal Differentiation in the Pacific Oyster .

BACKGROUND/OBJECTIVES: The Pacific oyster has emerged as a promising model system for sex determination studies due to its complex reproduction strategy and sex reversal. Transcription factors (TFs) play crucial roles in sex determination and gonadal differentiation. Despite previous research revealing functions of several conserved sex-determining pathway genes, such as , , and , little is known about the other essential TF regulators driving gonadal differentiation and development.

METHODS

In this study, a systematic identification of TFs revealed 1167 TF genes in the genome. Comparative transcriptome analysis of female and male gonads demonstrated 123 differentially expressed TF genes.

RESULTS

The majority of these sex-related TF genes were up-regulated in female or male gonads from the inactive stage to the mature stage. Moreover, this TF gene set was deeply conserved and showed similar regulation in the Kumamoto oyster gonads, suggesting their important regulatory roles in gonadal differentiation and development in Crassostrea oysters. Furthermore, two BTB TF gene clusters were identified in the genome, both of which were specifically expressed in the male gonad. Gene numbers of each BTB gene cluster showed significant variations among six Crassostrea species.

CONCLUSIONS

To the best of our knowledge, this study provides the first report of the whole TF family in . The sex-related TF gene set will be a valuable resource for further research aimed at uncovering TF gene regulatory networks in oyster sex determination and gonadal differentiation.