A Land Plant-Specific Transcription Factor Directly Enhances Transcription of a Pathogenic Noncoding RNA Template by DNA-Dependent RNA Polymerase II.
Some DNA-dependent RNA polymerases (DdRPs) possess RNA-dependent RNA polymerase activity, as was first discovered in the replication of Potato spindle tuber viroid (PSTVd) RNA genome in tomato (Solanum lycopersicum). Recent studies revealed that this activity in bacteria and mammals is important for transcriptional and posttranscriptional regulatory mechanisms. Here, we used PSTVd as a model to uncover auxiliary factors essential for RNA-templated transcription by DdRP PSTVd replication in the nucleoplasm generates (-)-PSTVd intermediates and (+)-PSTVd copies. We found that the Nicotiana benthamiana canonical 9-zinc finger (ZF) Transcription Factor IIIA (TFIIIA-9ZF) as well as its variant TFIIIA-7ZF interacted with (+)-PSTVd, but only TFIIIA-7ZF interacted with (-)-PSTVd. Suppression of TFIIIA-7ZF reduced PSTVd replication, and overexpression of TFIIIA-7ZF enhanced PSTVd replication in planta. Consistent with the locale of PSTVd replication, TFIIIA-7ZF was found in the nucleoplasm and nucleolus, in contrast to the strictly nucleolar localization of TFIIIA-9ZF. Footprinting assays revealed that only TFIIIA-7ZF bound to a region of PSTVd critical for initiating transcription. Furthermore, TFIIIA-7ZF strongly enhanced the in vitro transcription of circular (+)-PSTVd by partially purified Pol II. Together, our results identify TFIIIA-7ZF as a dedicated cellular transcription factor that acts in DdRP-catalyzed RNA-templated transcription, highlighting both the extraordinary evolutionary adaptation of viroids and the potential of DdRPs for a broader role in cellular processes.
Department of Molecular Genetics, Ohio State University, Columbus, Ohio 43210 The Center for RNA Biology, Ohio State University, Columbus, Ohio 43210 Center for Applied Plant Sciences, Ohio State University, Columbus, Ohio 43210 wang.974@osu.edu.
Ying
0000-0002-9659-977X
Y
Wang
Department of Molecular Genetics, Ohio State University, Columbus, Ohio 43210 Center for Applied Plant Sciences, Ohio State University, Columbus, Ohio 43210.
Jie
J
Qu
College of Life Sciences, Peking University, Beijing, China.
Shaoyi
S
Ji
Department of Chemistry and Biochemistry, Ohio State University, Columbus, Ohio 43210.
Andrew J
AJ
Wallace
Department of Molecular Genetics, Ohio State University, Columbus, Ohio 43210 Molecular, Cellular, and Developmental Biology Program, Ohio State University, Columbus, Ohio 43210.
Jian
J
Wu
College of Life Sciences, Peking University, Beijing, China.
Yi
Y
Li
The Center for RNA Biology, Ohio State University, Columbus, Ohio 43210 Department of Chemistry and Biochemistry, Ohio State University, Columbus, Ohio 43210 Molecular, Cellular, and Developmental Biology Program, Ohio State University, Columbus, Ohio 43210.
Venkat
V
Gopalan
Department of Molecular Genetics, Ohio State University, Columbus, Ohio 43210 The Center for RNA Biology, Ohio State University, Columbus, Ohio 43210 Center for Applied Plant Sciences, Ohio State University, Columbus, Ohio 43210 Molecular, Cellular, and Developmental Biology Program, Ohio State University, Columbus, Ohio 43210.
Biao
B
Ding
D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D012319:RNA Polymerase II / Q000235:genetics / Q000378:metabolism*; D022661:RNA, Untranslated / Q000235:genetics*; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism*; D035582:Transcription Factor TFIIIA / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D010940:Plant Proteins; D022661:RNA, Untranslated; D035582:Transcription Factor TFIIIA; D014157:Transcription Factors; D012319:RNA Polymerase II