Molecular Characterization of MyD88 in Pinctada fucata and its Response to Lipopolysaccharides and Polyinosinic-cytidylic Acid

Abstract

Myeloid differentiation factor 88 (MyD88) is a key and essential adapter involved in the interleukin-1 receptor (IL-1R) and toll-like receptor (TLR)-mediated activation signaling pathway. To investigate molecular characterization of MyD88 and its gene expression profile in response to stimulation by lipopolysaccharide (LPS) and polyinosinic-cytidylic acid (poly (I: C)), we isolated the MyD88 cDNA sequence in Pinctada fucata and analyzed expression patterns using quantitative real-time PCR. Sequence analysis indicated that Pf-MyD88 cDNA is 1463bp in length and contains a1050bp open reading frame that encodes a 349 α peptide. Pf-MyD88 has the highest similarity with homologues of Crassostrea gigas and highly conserved death and toll/IL-1R domains. Furthermore, during LPS and poly (I:C)-stimulated experiments in the gill, peak expression levels of Pf-MyD88 were detected at 2h and 8h with a 1.58-fold and 3.58-fold increase, respectively. The results revealed the existence of a MyD88-dependent signaling pathway in P. fucata and contributed to understanding the potential role of Pf-MyD88 in the TLR/IL-1R-mediated signaling pathway.