The heat shock transcription factor regulates the expression of crustin in Portunus trituberculatus.

Transcription factor is key regulatory component in immune signal transduction. To discover novel transcription factors that modulate antimicrobial peptide expression in crustaceans, we conduct the identification of heat shock transcription factor (HSF) in Portunus trituberculatus and investigated its regulatory role in antimicrobial peptide expression. The PtHSF exhibits typical structural characteristics of the HSF family, including a DNA-binding domain (DBD), hydrophobic repeats (HR-A/B), and a nuclear localization signal (NLS). The PtHSF widely expresses in multiple tissues, with notably high expression in muscle. Although Vibrio alginolyticus challenge does not induce significant changes in PtHSF expression levels in hemocytes of P. trituberculatus within 12 h, PtHSF specifically regulates the expression of Ptcrustin1 in hemocytes. Furthermore, molecular docking simulations reveal that three amino acids (His66, Arg103, and Lys104) in the DBD of PtHSF binds to the promoter sequence of Ptcrustin1 via noncovalent interactions, such as hydrogen bonds and Van der Waals forces. This study enriches the understanding of the regulatory mechanisms underlying antimicrobial peptide expression in crustaceans and provides novel perspectives for disease control in P. trituberculatus aquaculture.