RNA Binding Motif Protein, X-Linked 2 (RBMX2)

Complementary DNAs (cDNAs) corresponding to three isoforms of rock bream Mx (RbMx1, RbMx2 and RbMx3) were cloned using RACE reactions. Three rock bream Mx isoforms were encoded by different genomic loci, and they were not alternative splicing variants, although some alternative splicing variants were found in RbMx1 and RbMx2. When comparing amino acid sequence identity, RbMx1 shares about 60–70% identities with other fish Mx proteins, whereas both RbMx2 and RbMx3 share slightly high identity of 70–90%.  RbMx1 was constitutively expressed in the spleen and kidney of rock bream yearling, but RbMx2 and RbMx3 were rarely detected in both organs. RbMx1 was continuously up-regulated throughout experimental period of 72 h but RbMx2 and RbMx3 were down-regulated to almost non-detectable level at 48 h post-injection.