CXCR4 and infection: As miR-206 knockdown increased the expression of cxcl12a and cxcr4 genes, which are involved in neutrophil migration and retention of cells at sites of infection and inflammation [28,36–38], the neutrophil response to M. marinum infection in miR-206 knockdown treated embryos was assessed by live imaging of transgenic Tg(lyzC:GFP)nz117 or Tg(lyzC:DsRed2)nz50 embryos, where neutrophils are fluorescently labelled.