MicroRNA-1985 enhances the redox capability of scallop (Patinopecten yessoensis) in response to poly(I:C) stimulation by targeting MNK1

To clarify the microRNA (miRNA)-target gene axis is involved in response to pathogen-associated molecular pattern (PAMP)-induced oxidative stress in shellfish, the full-length cDNA of a novel <i>mitogen-activated protein kinase-interacting kinase</i> 1 (<i>MNK1</i>) homolog gene from the scallop <i>Patinopecten yessoensis</i> (<i>PyMNK1</i>) was cloned and characterized. The interaction between miR-1985 and <i>PyMNK1</i> was verified, and then the responses and possible molecular function of miR-1985, <i>PyMNK1</i>, and miR-1985/<i>PyMNK1</i> axis to poly(I:C) (a classic virus-related PAMP) stimulation in <i>P. yessoensis</i> were explored and preliminarily dissected. The results indicate: 1) The full-length cDNA of <i>PyMNK1</i> was 5354 bp, with a high level of sequence conservation across mollusks. 2) MiR-1985 bound to the 3'-UTR of <i>PyMNK1</i> and negatively regulated the expression of <i>PyMNK1</i>. 3) <i>Py</i>MNK1 may repress the relative expression of superoxide dismutase (<i>SOD</i>) by binding its promoter. 4) Both <i>PyMNK1</i> silencing and miR-1985 overexpression promoted the expression and enzymatic activity of SOD. 5) The miR-1985/<i>PyMNK1</i> axis may be involved in the response to poly(I:C) stimulation by elevating the activity of the SOD/catalase axis. To summarize, all observations from this study indicated that <i>P. yessoensis</i> may enhance its redox capability via the miR-1985/<i>PyMNK1</i>/SOD/CAT cascade and thereby alleviate PAMP-induced oxidative stress.