Tissue specific expression of SG2NA is regulated by differential splicing, RNA editing and differential polyadenylation

- 52 kDa SG2NA is generated by mRNA editing.
- SG2NAs have tissue specific repertoire that changes with aging.
- Sg2na transcripts are differentially polyadenylated.
- The Sg2na mRNAs with longer UTR are present only in mouse and chick brains.
- Expression of SG2NA is also regulated by mRNA/protein stability.

SG2NA belongs to a three member Striatin subfamily of WD-40 repeat superfamily. It has multiple protein-protein interaction domains that are involved in the assembly of supra-molecular signaling complexes. Earlier we had demonstrated that there are at least five variants of SG2NA, generated by alternative splicing. We now demonstrate that a 52 kDa novel variant is generated by the editing of the transcript for the 82 kDa isoform. The 52 kDa protein is abundant in mouse tissues but it is barely present in immortalized cells, suggesting its role in cell differentiation. Besides splicing and editing, expression of SG2NAs in tissues is also regulated by differential polyadenylation and mRNA/protein stability. Further, the longer UTR is seen only in the brain mRNA from 1 month old mouse and 8-10 day old chick embryo. Like alternative splicing, differential polyadenylation of Sg2na transcripts is also conserved in evolution. Taken together, these results suggest a highly versatile and dynamic mode of regulation of SG2NA with potential implications in tissue development.