Alternative splicing isoform of ADAR1-like computational and functional analysis in Ephinephelus malabaricus

In mammals, numerous ADAR1 splicing isoforms exist, including the constitutively expressed ∼110 kDa protein (ADAR1-p110) and the interferon (IFN)-inducible ∼150 kDa protein (ADAR1-p150). Their diverse roles may be associated with the structural variability of these isoforms. Fish also possess different ADAR1 splicing isoforms. In this study, we identified ADAR1 splicing isoforms (MgADAR1-like) in E. malabaricus. The full-length E. malabaricus ADAR1-like gene consists of a poly(A) tail, a 3084-bp open reading frame (ORF), a 210-bp 5′ untranslated region (5′ UTR), and a 521-bp 3′ untranslated region (3′ UTR). It encodes a polypeptide of 1027 amino acids with a predicted molecular weight of 111.11 kDa and a theoretical isoelectric point of 7.78. Using real-time quantitative RT-PCR, we examined the transcriptional regulation of the EmADAR1-like alternative splicing (AS) gene following immunostimulation and NNV infection. EmADAR1-like mRNA expression peaked at 12–24 h post-infection and was markedly upregulated. Additionally, we investigated the potential mechanism of IFN signaling in grouper kidney cells, as well as the ability of IFN or NNV to regulate splicing isoforms. The knowledge about structure and expression of EmADAR1-like in the grouper provides coherent framework to further dissect its roles in immune response.