Characterization and expression analysis of tandemly duplicated nicotinic acetylcholine receptors in pearl oysters after stimulation of pathogen-related molecular patterns

Nicotinic acetylcholine receptors (nAChRs) are a class of ligand-gated ion channels that participate in signal transduction and reported to play an important role the immunomodulation vertebrates invertebrates. Previous studies have shown nAChRs mollusks undergone large-scale expansion after tandem repeats retrotransposition, with most observed bivalves. This study characterized sequence repeat nAChR unique several bivalve investigated its functions Pinctada fucata martensii. Firstly, phylogenetic analysis revealed arrays existed before differentiation m ost tandem-replicated genes conserved genomic structure domain combination. In present study, five tandemly duplicated were cloned from P. f. martensii designated as PmnAChR-1 PmnAChR-5. qRT-PCR PmnAChRs specifically expressed adult gills. addition, PAMP stimulation, expression hemocytes strongly induced but exhibited different responses stimuli. PmnAChR-1, PmnAChR-4, PmnAChR-5 strong wide responsiveness lipopolysaccharide (LPS) stimulation had no response peptidoglycan (PGN) stimulation. PmnAChR-2 was notably upregulated at 6 h PGN challenge LPS Polyinosinic-polycytidylic acid nearly all PmnAChRs, except for Furthermore, Pm-miR-873-3p, Pm-miR-4577, Pm-miR-103a-3p, Pm-miR-6753-3p identified regulatory miRNA PmnAChR-3, PmnAChR-5, respectively. These findings suggested these bivalves, duplication may be involved immune regulation process pathogen