MmuEX0023092 @ mm9

The inclusion of exon 2 (HsaEX0030279) and exon 9 (HsaEX0030282) generates a predominantly nuclear form, skipping of the exons generates cytosolic forms. The study shows, using isoform-specific antibodies and isoform-specific green fluorescent protein (GFP)-fusion expression constructs, that A2b is the predominant cytoplasmic isoform in neural cells, suggesting that it may play a key role in mRNA trafficking. The differential subcellular distribution patterns of the individual isoforms are determined by the presence or absence of alternative exons that also affect their dynamic behavior in different cellular compartments, as measured by fluorescence correlation spectroscopy. Expression of A2b is also differentially regulated with age, species and cellular development. Furthermore, coinjection of isoform-specific antibodies and labeled RNA into live oligodendrocytes shows that the assembly of RNA granules is impaired by blockade of A2b function. These findings suggest that neural cells modulate mRNA trafficking by regulating alternative splicing of hnRNP A2/B1 and controlling expression levels of A2b, which may be the predominant mediator of cytoplasmic-trafficking functions. B1: inclusion of both. A2: skipping of ex 2. B1b: skipping of ex 9. A2b: skipping of both. Not well in VTS in hg38 nor mm10.