Figure 2.

Representation of cellular condensates formed by liquid/liquid phase separation. The formation of transcriptional condensates occurs through the association of the intrinsically disordered regions of mediator, RNA pol II, and the transcription factors that form the pre-initiation complex (PIC), including transcription initiation factor IIA (TFIIA), TFIIB, TFIID (which is composed by TBP and the 14 TBP-associated factors), TFIIE, TFIIF, and TFIIH (which contains CDK7). The phosphorylation of the CTD-terminal of RNA pol II by CDK7 and CDK9 enables the RNA pol II to escape promoter-pausing and enroll transcription elongation. When RNA pol II transcribes the polyadenylation signal (PAS), being released from the DNA template, it produces a signal to terminate transcription. Closely associated with transcriptional condensates are the nuclear speckles, small reservoirs of splicing factors (SFs), RNA-binding proteins (RBPs), and small nuclear ribonucleoproteins (snRNP), and paraspeckles, all having a fundamental role in the mRNA processing. There are other membraneless organelles in the cell formed by LLPS, such as cleavage bodies, perinuclear compartments, Cajal bodies, nucleoli, histone locus bodies, nuclear stress bodies, and stress granules.