Essential transcriptional regulators of cement proteins during barnacle settlement

Abstract

Underwater bioadhesion, which is a vital property for the survival and reproduction of many aquatic benthic organisms, has inspired the design of biomimetic materials. However, there is little information on the transcriptional regulatory mechanisms governing the expression of bioadhesives. Barnacles are well known for their strong adhesion to marine substrates, which arises from their unique cement proteins (CPs). In this work, we identified 145 transcription factors (TFs) that were potentially associated with cyprid settlement in the barnacle Amphibalanus amphitrite using genome-wide TF screening combined with weighted gene co-expression network analysis (WGCNA). Specifically, we demonstrated that PRRX2 activated the expression of a barnacle CP, Aacp19k-like, by binding to an AATTA motif located between −185 and −181 bp of its promoter. The gene expression of another CP gene, Aacp100k, was positively regulated by two TFs, SGF3 and NKX6.2, which targeted distinct cis-elements of TATGAA at −560 to −555 bp and CTCATCAAC at +325 to +333 bp, respectively. In vivo localization and RNA interference assays further confirmed that PRRX2, SGF3, and NKX6.2 are essential for cyprid settlement, as evidenced by their co-localization with Aacp19k-like and Aacp100k in the cement glands and the significant decrease in settlement rates that occurs following knockdown of these genes. Phylogenetic analysis indicated the conservation of PRRX2, SGF3, and NKX6.2 within different barnacle species. Overall, the findings of this study reveal the key transcriptional regulators of barnacle CPs and provide new mechanistic insights into underwater adhesion.

Keywords

Underwater adhesion / Cement proteins / Transcriptional regulation / Cyprid settlement

References

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