Genomic structural characterization and transcriptional expression analysis of proteasome activator PA28 alpha and PA28 beta subunits from Oplegnathus fasciatus

Abstract

Proteasomes are multicatalytic subunit complexes involved in the degradation of cytosolic proteins and antigen presentation. In this study, we have characterized the alpha and beta subunits of proteasome activator complex from rock bream at the molecular level. RbPA28 alpha and RbPA28 beta possessed the characteristic features of the subunits identified from mammals and teleosts. The RbPA28 alpha and RbPA28 beta proteasome subunits contained a proline-rich motif (Region A), subunit-specific insert in the region corresponding to the KEKE motif of the known PA28 alpha (Region B), conserved activation loop (Region C), a potential protein kinase C recognition site (Region D) and a highly homologous C-terminal region (Region E) among all three PA28 subunits. Multiple sequence alignment and pairwise alignment revealed that RbPA28 alpha and RbPA28 beta proteins shared high homology with the teleosts and mammals. RbPA28 alpha and RbPA28 beta genome possessed 11 exons interrupted by 10 introns. In silico promoter analysis of RbPA28 alpha and RbPA28 beta revealed various transcription factor-binding sites displaying their regulation under various stress conditions. Tissue distribution profiling showed a higher expression in blood and gills. Transcriptional expression analysis of RbPA28 alpha and RbPA28 beta showed up-regulation in the immune tissues following LPS and poly I:C challenges, providing further evidence for the immunological role of RbPA28 alpha and RbPA28 beta. (C) 2013 Elsevier Ltd. All rights reserved.