CASP9 and coinfection: Concurrent analyses of apoptotic gene regulation revealed that zfhnf4α, like its grass carp ortholog, transcriptionally controls core apoptotic effectors: qRT-PCR showed zfhnf4α deficiency significantly reduced infection-induced mRNA levels of aif, caspase 3, and caspase 9 in both single (A. salmonicida or GCRV-II) and co-infection models (Fig 9C-9E).