Rebecca A Mosher

Rebecca A Mosher

Associate Professor, Plant Sciences
Associate Director, School of Plant Sciences
Associate Professor, Applied BioSciences - GIDP
Associate Professor, Genetics - GIDP
Associate Professor, BIO5 Institute
Primary Department
Department Affiliations
Contact
(520) 626-4185

Work Summary

Dr. Mosher studies methylation of DNA in plants and how these epigenetic marks are transmitted from parent to offspring.

Research Interest

Rebecca Mosher, PhD, studies how epigenetic information is passed from parent to offspring. Epigenetic information refers to signals laid on top of DNA sequence that affect how and when genes are turned on. Examples of epigenetic signals include chemical modifications of DNA, packaging of DNA around proteins, or the position of DNA in the nucleus. Beginning with Mendel’s observations of pea plants, we have developed a robust understanding of how genetic information in the form of DNA is passed from parent to offspring, but we are only beginning to comprehend how and when epigenetic information is passed from generation to generation. Some epigenetic marks are erased and re-established during reproduction, while others are inherited for many generations. Using plants as models, the Mosher lab studies how tiny RNA molecules place and erase epigenetic marks during reproduction and how the epigenetic marks from the maternal and paternal genomes interact after fertilization.

Publications

Gohlke, J., & Mosher, R. A. (2015). Exploiting mobile RNA silencing for crop improvement. American Journal of Botany (review article), 102(9), 1399-400. doi:10.3732/ajb.1500173
Mosher, R. A. (2012). Pinpointing a puzzling polymerase. Nature Structural and Molecular Biology, 19(9), 865-866.
Mosher, R. A. (2014). An Interview with Rebecca Mosher (review article). Trends in Plant Science.
Preuss, S. B., Costa-Nunes, P., Tucker, S., Pontes, O., Lawrence, R. J., Mosher, R., Kasschau, K. D., Carrington, J. C., Baulcombe, D. C., Viegas, W., & Pikaard, C. S. (2008). Multimegabase Silencing in Nucleolar Dominance Involves siRNA-Directed DNA Methylation and Specific Methylcytosine-Binding Proteins. Molecular Cell, 32(5), 673-684.

PMID: 19061642;PMCID: PMC2741319;Abstract:

In genetic hybrids, the silencing of nucleolar rRNA genes inherited from one progenitor is the epigenetic phenomenon known as nucleolar dominance. An RNAi knockdown screen identified the Arabidopsis de novo cytosine methyltransferase, DRM2, and the methylcytosine binding domain proteins, MBD6 and MBD10, as activities required for nucleolar dominance. MBD10 localizes throughout the nucleus, but MBD6 preferentially associates with silenced rRNA genes and does so in a DRM2-dependent manner. DRM2 methylation is thought to be guided by siRNAs whose biogenesis requires RNA-DEPENDENT RNA POLYMERASE 2 (RDR2) and DICER-LIKE 3 (DCL3). Consistent with this hypothesis, knockdown of DCL3 or RDR2 disrupts nucleolar dominance. Collectively, these results indicate that in addition to directing the silencing of retrotransposons and noncoding repeats, siRNAs specify de novo cytosine methylation patterns that are recognized by MBD6 and MBD10 in the large-scale silencing of rRNA gene loci. © 2008 Elsevier Inc. All rights reserved.

Searle, I. R., Mosher, R. A., Melnyk, C. W., & Baulcombe, D. C. (2007). Small RNAs hit the big time: Meetings. New Phytologist, 174(3), 479-482.