RESUMO
Integrator is a multi-subunit protein complex responsible for premature transcription termination of coding and non-coding RNAs. This is achieved via two enzymatic activities, RNA endonuclease and protein phosphatase, acting on the promoter-proximally paused RNA polymerase â ¡ (RNAPâ ¡). Yet, it remains unclear how Integrator assembly and recruitment are regulated and what the functions of many of its core subunits are. Here, we report the structures of two human Integrator sub-complexes: INTS10/13/14/15 and INTS5/8/10/15, and an integrative model of the fully assembled Integrator bound to the RNAPâ ¡ paused elongating complex (PEC). An in silico protein-protein interaction screen of over 1,500 human transcription factors (TFs) identified ZNF655 as a direct interacting partner of INTS13 within the fully assembled Integrator. We propose a model wherein INTS13 acts as a platform for the recruitment of TFs that could modulate the stability of the Integrator's association at specific loci and regulate transcription attenuation of the target genes.
Assuntos
Ligação Proteica , RNA Polimerase II , Fatores de Transcrição , Humanos , RNA Polimerase II/metabolismo , RNA Polimerase II/genética , RNA Polimerase II/química , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/química , Modelos Moleculares , Microscopia Crioeletrônica , Regiões Promotoras Genéticas , Células HEK293 , Sítios de Ligação , EndorribonucleasesRESUMO
The 20S U5 small nuclear ribonucleoprotein particle (snRNP) is a 17-subunit RNA-protein complex and a precursor of the U4/U6.U5 tri-snRNP, the major building block of the precatalytic spliceosome. CD2BP2 is a hallmark protein of the 20S U5 snRNP, absent from the mature tri-snRNP. Here we report a high-resolution cryogenic electron microscopy structure of the 20S U5 snRNP, shedding light on the mutually exclusive interfaces utilized during tri-snRNP assembly and the role of the CD2BP2 in facilitating this process.
