Two small regulatory RNAs establish opposing fates of a developmental axis
- Fabio T.S. Nogueira1,3,
- Shahinez Madi1,3,
- Daniel H. Chitwood1,2,
- Michelle T. Juarez1,4, and
- Marja C.P. Timmermans1,2,5
- 1 Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA;
- 2 Watson School of Biological Sciences, Cold Spring Harbor, New York 11724, USA
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↵3 These authors contributed equally to this work.
Abstract
Small RNAs are important regulators of gene expression. In maize, adaxial/abaxial (dorsoventral) leaf polarity is established by an abaxial gradient of microRNA166 (miR166), which spatially restricts the expression domain of class III homeodomain leucine zipper (HD-ZIPIII) transcription factors that specify adaxial/upper fate. Here, we show that leafbladeless1 encodes a key component in the trans-acting small interfering RNA (ta-siRNA) biogenesis pathway that acts on the adaxial side of developing leaves and demarcates the domains of hd-zipIII and miR166 accumulation. Our findings indicate that tasiR-ARF, a ta-siRNA, and miR166 establish opposing domains along the adaxial–abaxial axis, thus revealing a novel mechanism of pattern formation.
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Footnotes
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↵4 Present address: Cell and Developmental Biology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
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↵5 Corresponding author.
↵5 E-MAIL timmerma{at}cshl.edu; FAX (516) 367-8369.
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Supplemental material is available at www.genesdev.org.
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Article is online at http://www.genesdev.org/cgi/doi/10.1101/gad.1528607
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- Received January 8, 2007.
- Accepted February 20, 2007.
- Copyright © 2007, Cold Spring Harbor Laboratory Press
