scholarly journals Cryo-EM Structures Reveal Transcription Initiation Steps by Yeast Mitochondrial RNA Polymerase

2020 ◽  
Author(s):  
Brent De Wijngaert ◽  
Shemaila Sultana ◽  
Chhaya Dharia ◽  
Hans Vanbuel ◽  
Jiayu Shen ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Transcription Initiation ◽  
Mitochondrial Rna ◽  
Mitochondrial Rna Polymerase

scholarly journals Cryo-EM structures reveal transcription initiation steps by yeast mitochondrial RNA polymerase

2020 ◽  
Author(s):  
Brent De Wijngaert ◽  
Shemaila Sultana ◽  
Chhaya Dharia ◽  
Hans Vanbuel ◽  
Jiayu Shen ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Transcription Initiation ◽  
Large Scale ◽  
Rna Synthesis ◽  
Mitochondrial Rna ◽  
Initiation Complex ◽  
Mitochondrial Rna Polymerase ◽  
Catalytically Active ◽  
Promoter Melting ◽  
Antiviral Nucleosides

Cryo-EM structures of transcription pre-initiation complex (PIC) and initiation complex (IC) of yeast mitochondrial RNA polymerase show fully resolved transcription bubbles and explain promoter melting, template alignment, DNA scrunching, transition into elongation, and abortive synthesis. Promoter melting initiates in PIC with MTF1 trapping the −4 to −2 non-template (NT) bases in its NT-groove. Transition to IC is marked by a large-scale movement that aligns the template with RNA at the active site. RNA synthesis scrunches the NT strand into an NT-loop, which interacts with centrally positioned MTF1 C-tail. Steric clashes of the C-tail with RNA:DNA and NT-loop, and dynamic scrunching-unscrunching of DNA explain abortive synthesis and transition into elongation. Capturing the catalytically active IC-state with UTPαS poised for incorporation enables modeling toxicity of antiviral nucleosides/nucleotides.

scholarly journals A novel intermediate in transcription initiation by human mitochondrial RNA polymerase

2014 ◽  
Vol 42 (6) ◽  
pp. 3884-3893 ◽  
Author(s):  
Yaroslav I. Morozov ◽  
Karen Agaronyan ◽  
Alan C. M. Cheung ◽  
Michael Anikin ◽  
Patrick Cramer ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Transcription Initiation ◽  
Mitochondrial Rna ◽  
Mitochondrial Rna Polymerase

scholarly journals The N-terminal Domain of the Yeast Mitochondrial RNA Polymerase Regulates Multiple Steps of Transcription

2011 ◽  
Vol 286 (18) ◽  
pp. 16109-16120 ◽  
Author(s):  
Swaroopa Paratkar ◽  
Aishwarya P. Deshpande ◽  
Guo-Qing Tang ◽  
Smita S. Patel
Keyword(s):  
Amino Acids ◽  
Rna Polymerase ◽  
Transcription Initiation ◽  
Rna Synthesis ◽  
Full Length ◽  
Mitochondrial Rna ◽  
Terminal Domain ◽  
Mitochondrial Rna Polymerase

Transcription of the yeast (Saccharomyces cerevisiae) mitochondrial (mt) genome is catalyzed by nuclear-encoded proteins that include the core RNA polymerase (RNAP) subunit Rpo41 and the transcription factor Mtf1. Rpo41 is homologous to the single-subunit bacteriophage T7/T3 RNAP. Its ∼80-kDa C-terminal domain is highly conserved among mt RNAPs, but its ∼50-kDa N-terminal domain (NTD) is less conserved and not present in T7/T3 RNAP. To understand the role of the NTD, we have biochemically characterized a series of NTD deletion mutants of Rpo41. Our studies show that NTD regulates multiple steps of transcription initiation. Interestingly, NTD functions in an autoinhibitory manner during initiation, and its partial deletion increases the efficiency of RNA synthesis. Deletion of 1–270 amino acids (DN270) reduces abortive synthesis and increases full-length to abortive RNA ratio relative to full-length (FL) Rpo41. A larger deletion of 1–380 amino acids (DN380), decreases RNA synthesis on duplex but not on premelted promoter. We show that DN380 is defective in promoter opening near the transcription start site. Most strikingly, both DN270 and DN380 catalyze highly processive RNA synthesis on the premelted promoter, and unlike the FL Rpo41, the mutants are not inhibited by Mtf1. Both mutants show weaker interactions with Mtf1, which explains many of our results, and particularly the ability of the mutants to efficiently transition from initiation to elongation. We propose that in vivo the accessory proteins that bind NTD may modulate interactions of Rpo41 with the promoter/Mtf1 to activate and allow timely release from Mtf1 for transition into elongation.

scholarly journals The amino terminal extension of mammalian mitochondrial RNA polymerase ensures promoter specific transcription initiation

2014 ◽  
Vol 42 (6) ◽  
pp. 3638-3647 ◽  
Author(s):  
Viktor Posse ◽  
Emily Hoberg ◽  
Anke Dierckx ◽  
Saba Shahzad ◽  
Camilla Koolmeister ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Transcription Initiation ◽  
Mitochondrial Rna ◽  
Amino Terminal ◽  
Mitochondrial Rna Polymerase

scholarly journals Cryo-EM Structures Reveal Transcription Initiation Steps by Yeast Mitochondrial RNA Polymerase

2020 ◽  
Author(s):  
Brent De Wijngaert ◽  
Shemaila Sultana ◽  
Anupam Singh ◽  
Chhaya Dharia ◽  
Hans Vanbuel ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Transcription Initiation ◽  
Mitochondrial Rna ◽  
Mitochondrial Rna Polymerase
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