Poster abstracts
Poster number 44 submitted by Ben Oakes
The role of RNA polymerase IV in effecting heritable regulatory changes
Benjamin P. Oakes (Molecular, Cellular and Developmental Biology Graduate Program, The Ohio State University, Columbus, Ohio 43210), Jay B. Hollick (Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210; Centers for RNA Biology and Applied Plant Sciences, The Ohio State University, Columbus, Ohio 43210)
Abstract:
Paramutation is a behavior in which one parental allele at a given locus facilitates a meiotically heritable change at the other1. This behavior occurs at specific alleles of multiple maize loci encoding transcriptional activators of flavonoid biosynthesis including red1 (r1), booster1 (b1), purple plant1 (pl1), and pericarp color1 (p1)2. The Pl1-Rhoades (Pl1-Rh) allele can exist in a highly expressed reference state (Pl-Rh) or an epigenetically repressed paramutant state (denoted Pl′ )3. Pl1-Rh alleles in the Pl′ state often revert to Pl-Rh in plants homozygous for a null allele (rmr6-1) of a gene encoding the RNA polymerase (RNAP) IV largest subunit4 indicating that RNAP IV maintains the heritable information specifying Pl1-Rh paramutation. Because RNAP IV both sources 24 nucleotide RNAs5 and controls the heritable regulatory status of Pl1-Rh4, we hypothesize that RNAP IV, and potentially small RNAs (sRNAs) in general, condition the inheritance of genome-wide regulatory information. To test this idea, seedling RNA-seq and sRNA-seq profiles of heterozygous BC5 progeny from sibling rmr6-1 mutant and heterozygous fathers were compared to identify heritable RNAP IV-dependent effects. RNA abundances of 140 genes were either significantly enriched or depleted in the progeny of mutant rmr6-1 fathers as compared to progeny of heterozygous fathers. Additionally, 962 sRNA clusters were significantly enriched or depleted in an identical comparison. These differences point to other alleles, like Pl1-Rh, whose dysregulation in the absence of RNAP IV might persist through meiosis. Future studies aim to determine the role of environmental factors in effecting heritable changes at Pl1-Rh and other alleles as Bernard Mikula showed that the extent of heritable changes brought about by paramutations occurring at r1 is influenced by the environment during early development6.
References:
1. Brink Genetics (1956) | 2. Hollick Nat Rev Gen (2017) | 3. Hollick et al. Genetics (1995) | 4. Hollick et al. Genetics (2005) | 5. Erhard et al. Science (2009) | 6. Mikula Genetics (1995)
Keywords: Epigenetics, Paramutation, Inheritance