REH2 RNA helicase in kinetoplastid mitochondria: ribonucleoprotein complexes and essential motifs for unwinding and guide RNA (gRNA) binding.
Regulation of gene expression in kinetoplastid mitochondria is largely post-transcriptional and involves the orchestration of polycistronic RNA processing, 3'-terminal maturation, RNA editing, turnover, and translation; however, these processes remain poorly studied. Core editing complexes and their U-insertion/deletion activities are relatively well characterized, and a battery of ancillary factors has recently emerged. This study characterized a novel DExH-box RNA helicase, termed here REH2 (RNA editing associated helicase 2), in unique ribonucleoprotein complexes that exhibit unwinding and guide RNA binding activities, both of which required a double-stranded RNA-binding domain (dsRBD) and a functional helicase motif I of REH2. REH2 complexes and recently identified related particles share a multiprotein core but are distinguished by several differential polypeptides. Finally, REH2 associates transiently, via RNA, with editing complexes, mitochondrial ribosomes, and several ancillary factors that control editing and RNA stability. We propose that these putative higher order structures coordinate mitochondrial gene expression.
Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843, USA.
Alfredo
A
Hernandez
Bhaskara Reddy
BR
Madina
Kevin
K
Ro
James A
JA
Wohlschlegel
Belinda
B
Willard
Mike T
MT
Kinter
Jorge
J
Cruz-Reyes
D020816:Amino Acid Motifs / Q000502:physiology; D000818:Animals; D008928:Mitochondria / Q000201:enzymology* / Q000235:genetics; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary / Q000502:physiology; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D017393:RNA Editing / Q000502:physiology; D020365:RNA Helicases / Q000235:genetics / Q000378:metabolism*; D020871:RNA Stability / Q000502:physiology; D017394:RNA, Guide, Kinetoplastida / Q000235:genetics / Q000378:metabolism; D016053:RNA, Protozoan / Q000235:genetics / Q000378:metabolism; D012261:Ribonucleoproteins / Q000235:genetics / Q000378:metabolism*; D012270:Ribosomes / Q000235:genetics / Q000378:metabolism; D014346:Trypanosoma brucei brucei / Q000201:enzymology* / Q000235:genetics
D024101:Mitochondrial Proteins; D015800:Protozoan Proteins; D016053:RNA, Protozoan; D012261:Ribonucleoproteins; D020365:RNA Helicases; D017394:RNA, Guide, Kinetoplastida