The histone proteins are responsible for the compaction and functional organization of DMA in the nucleus. These small, evolutionary conserved proteins are host to a diverse array of post-translational modifications, each of which is typically associated with a specific DNA-templated process, such as gene regulation. We recently discovered a novel mammalian gene silencing pathway mediated by the PR-Set7 enzyme that specifically monomethylates histone H4 lysine 20 (H4K20). Our new findings indicate that this silencing pathway is targeted to the promoters of certain genes that function in growth and differentiation programs. Based on these findings, our central hypothesis is that one major role of H4K20 monomethylation is to maintain cellular identity by repressing specific sets of genes that promote growth and differentiation. The goal of this proposal is to dissect the molecular mechanisms of this fundamental gene silencing pathway with the long range goal of determining the role of this pathway in establishing and maintaining cellular identity. We recently discovered that PR-Set7 associates with a novel histone H3 lysine 9 (H3K9) methyltransferase to create a repressive monomethyl-H4K20 and H3K9 """"""""trans-tail histone code"""""""" at gene promoters.
In Aim 1 we will use established molecular and biochemical methods to identify and characterize this enzyme and determine its in vivo role in gene repression. We have also discovered the first known H4K20 monomethyl- binding protein, L(3)MBT, and determined that this interaction is essential for gene repression.
In Aim 2 we will define the regions and amino acids of L(3)MBT required for binding monomethylated H4K20 and gene repression.
In Aim 3 we will continue to identify additional genes regulated by this silencing pathway. These genes serve as the in vivo models to dissect apart the individual contributions of each of the components of this pathway on in vivo gene repression. Collectively, this proposal will illuminate the molecular mechanisms of a fundamental mammalian gene regulation pathway involved in critical biological processes and will likely have far-reaching and wide-spread impacts on human health and disease.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Research Project (R01)
Project #
Application #
Study Section
Molecular Genetics A Study Section (MGA)
Program Officer
Carter, Anthony D
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Southern California
Schools of Medicine
Los Angeles
United States
Zip Code
Congdon, Lauren M; Sims, Jennifer K; Tuzon, Creighton T et al. (2014) The PR-Set7 binding domain of Riz1 is required for the H4K20me1-H3K9me1 trans-tail 'histone code' and Riz1 tumor suppressor function. Nucleic Acids Res 42:3580-9
Tuzon, Creighton T; Spektor, Tanya; Kong, Xiaodong et al. (2014) Concerted activities of distinct H4K20 methyltransferases at DNA double-strand breaks regulate 53BP1 nucleation and NHEJ-directed repair. Cell Rep 8:430-8
Blum, Gil; Ibáñez, Glorymar; Rao, Xiangjun et al. (2014) Small-molecule inhibitors of SETD8 with cellular activity. ACS Chem Biol 9:2471-8
Lin, Shuibin; Shen, Huangxuan; Li, Jian-Liang et al. (2013) Proteomic and functional analyses reveal the role of chromatin reader SFMBT1 in regulating epigenetic silencing and the myogenic gene program. J Biol Chem 288:6238-47
Brusslan, Judy A; Rus Alvarez-Canterbury, Ana M; Nair, Nishanth Ulhas et al. (2012) Genome-wide evaluation of histone methylation changes associated with leaf senescence in Arabidopsis. PLoS One 7:e33151
Wu, Shumin; Rice, Judd C (2011) A new regulator of the cell cycle: the PR-Set7 histone methyltransferase. Cell Cycle 10:68-72
Spektor, Tanya M; Congdon, Lauren M; Veerappan, Chendhore S et al. (2011) The UBC9 E2 SUMO conjugating enzyme binds the PR-Set7 histone methyltransferase to facilitate target gene repression. PLoS One 6:e22785
Lucio-Eterovic, Agda Karina; Singh, Melissa M; Gardner, Jeffrey E et al. (2010) Role for the nuclear receptor-binding SET domain protein 1 (NSD1) methyltransferase in coordinating lysine 36 methylation at histone 3 with RNA polymerase II function. Proc Natl Acad Sci U S A 107:16952-7
Congdon, Lauren M; Houston, Sabrina I; Veerappan, Chendhore S et al. (2010) PR-Set7-mediated monomethylation of histone H4 lysine 20 at specific genomic regions induces transcriptional repression. J Cell Biochem 110:609-19
Wu, Shumin; Wang, Weiping; Kong, Xiangduo et al. (2010) Dynamic regulation of the PR-Set7 histone methyltransferase is required for normal cell cycle progression. Genes Dev 24:2531-42

Showing the most recent 10 out of 16 publications