Nuclear Speckles enable processing of RNA from GC-rich Isochores [SON_Halo_pSR_SF3B1_FLASH]

Investigating the direct role of Speckles in these processes have been intractable due to their heterogeneous, multi-component nature. Here we show that Speckles are necessary for the splicing of GC-rich, levelled intron/exon architecture.

Acute removal of Speckles leads to a drastic downregulation of GC-rich genes which are clustered within GC-rich isochores. Genes outside these domains are physically away from Speckles and are not affected from loss of Speckles. Animal genomes that do not have GC-rich isochores, do not have GC-rich levelled intron/exon architecture and do not have Speckles.