Cytoplasmic Polyadenylation Element Binding Protein 3 (CPEB3)

By sequencing clones obtained from a size-fractionated adult brain cDNA library, Nagase et al. (1999) cloned CPEB3, which they designated KIAA0940. RT-PCR ELISA detected high expression in brain, intermediate expression in kidney, heart, lung, liver, skeletal muscle, testis, ovary, pancreas, and fetal liver, and low expression in spleen and fetal brain. CPEB3 was expressed in all specific adult brain regions examined, with highest levels in amygdala and substantia nigra. CPEB3 transcripts use 2 alternate untranslated first exons, one expressed in liver and testis, and the other expressed in brain. The 698-amino acid CPEB3 protein has an N-terminal glutamine-rich domain, followed by 2 RNA recognition motifs and a C-terminal zinc finger domain. The glutamine-rich domain is not present in other CPEBs.