Functional characterization of transcription initiation factor TFIID subunit 7 in Penaeus vannamei (PvTAF7) and its interaction with YY1 in response to Vibrio challenge.

The whiteleg shrimp (Penaeus vannamei) is one of the most economically important aquaculture species worldwide. Transcription initiation factor TFIID subunit 7 (TAF7), a core component of the TFIID complex, is known to regulate transcription through interactions with other transcription factors. However, its role in crustacean immunity remains largely unexplored. In this study, we cloned and functionally characterized a TAF7 homolog from P. vannamei, designated as PvTAF7. The gene comprises an open reading frame (ORF) of 1110 bp, encoding a 369-amino-acid protein containing a conserved TAFⅡ55 domain. Phylogenetic analysis clustered PvTAF7 within the Decapoda clade, indicating strong evolutionary conservation among crustaceans. Tissue distribution analysis showed that PvTAF7 is highly expressed in the hepatopancreas and hemocytes, key immune tissues in shrimp. PvTAF7 expression was significantly upregulated in response to Vibrio parahaemolyticus (including the AHPND strain) in both hemocytes and hepatopancreas. RNA interference-mediated knockdown of PvTAF7 led to reduced expression of immune-related genes, including lysozyme, crustins, hemocyanins, and the transcription factor PvYY1, and resulted in increased mortality following Vibrio infection. Moreover, GST pull-down assays and structural modeling demonstrated that PvTAF7 interacts with PvYY1 via its TAFⅡ55 domain and the zinc finger domain of PvYY1, forming a functional protein complex. Collectively, these findings reveal that PvTAF7 plays a critical role in the antibacterial immune response of P. vannamei, likely by regulating immune gene expression through its interaction with PvYY1.