About the Authors

Zhixin Xie

Contributed equally to this work with: Zhixin Xie, Lisa K Johansen

Affiliation Center for Gene Research and Biotechnology and Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America

Lisa K Johansen

Contributed equally to this work with: Zhixin Xie, Lisa K Johansen

Affiliation Center for Gene Research and Biotechnology and Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America

Adam M Gustafson

Affiliation Center for Gene Research and Biotechnology and Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America

Kristin D Kasschau

Affiliation Center for Gene Research and Biotechnology and Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America

Andrew D Lellis

Affiliation Center for Gene Research and Biotechnology and Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America

Daniel Zilberman

Affiliation Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, California, United States of America

Steven E Jacobsen

Affiliations Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, California, United States of America, Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California, United States of America

James C Carrington

To whom correspondence should be addressed. E-mail: carrington@cgrb.oregonstate.edu

Affiliation Center for Gene Research and Biotechnology and Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America

Competing Interests

The authors have declared that no conflicts of interest exist.

Author Contributions

ZX, LKJ, KDK, and JCC conceived and designed the experiments. ZX, LKJ, KDK, and ADL did most of the experimental work. AMG, KDK, and JCC conceived and designed the small RNA database. AMG constructed the database. DZ and SEJ generated the ago4-1 and cmt3-7 mutants and developed chromatin analysis protocols. ZX, LKJ, KDK, JCC, and SEJ analyzed the data. ZX and JCC wrote the paper.