KREPA6 is an RNA-binding protein essential for editosome integrity and survival of Trypanosoma brucei.
Most mitochondrial mRNAs in kinetoplastid protozoa require post-transcriptional RNA editing that inserts and deletes uridylates, a process that is catalyzed by multiprotein editosomes. KREPA6 is the smallest of six editosome proteins that have predicted oligonucleotide-binding (OB) folds. Inactivation of KREPA6 expression results in disruption and ultimate loss of approximately 20S editosomes and inhibition of procyclic form cell growth. Gel shift studies show that recombinant KREPA6 binds RNA, but not DNA, with a preference for oligo-(U) whether on the 3' end of gRNA or as a (UU)(12) homopolymer. Thus, KREPA6 is essential for the structural integrity and presence of approximately 20S editosomes and for cell viability. It functions in RNA binding perhaps primarily through the gRNA 3' oligo(U) tail. The significance of these findings to key steps in editing is discussed.
Seattle Biomedical Research Institute, Seattle, Washington 98109, USA
Salvador Zipagan
SZ
Tarun
Achim
A
Schnaufer
Nancy Lewis
NL
Ernst
Rosemary
R
Proff
Junpeng
J
Deng
Wim
W
Hol
Kenneth
K
Stuart
D000818:Animals; D002470:Cell Survival; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D017393:RNA Editing; D034622:RNA Interference; D016053:RNA, Protozoan / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D014346:Trypanosoma brucei brucei / Q000235:genetics* / Q000378:metabolism
D015800:Protozoan Proteins; D016053:RNA, Protozoan; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins