Genome rearrangements are mutations that cause numerous genetic diseases including cancer, immune deficiencies and developmental disorders. Genome rearrangements are caused by defects in DNA replication and repair pathways, as well as the presence of numerous at-risk sequences in the human genome that are prone to mutations. Protein sumoylation is reversible and involves the opposing actions of two families of enzymes; the E3 ligases that catalyze the attachment of Small Ubiquitin-like MOdifier (SUMO) to substrates, and the SUMO specific proteases that remove them. Our genetic study using Saccharomyces cerevisiae has identified a major role of these enzymes in preventing diverse genome rearrangements, and has further uncovered a new paradigm in which spontaneous DNA breaks occurred during DNA replication caused these genome rearrangements. Additionally, results from our proteomic and biochemical studies have identified the Mini-Chromosome Maintenance (MCM) complex at the DNA replication fork as a major target under the regulation of SUMO. Because inherited mutations of genes in the SUMO pathways cause genome instability syndrome in mammals, understanding the molecular basis by which protein sumoylation regulates DNA replication will impact human health for two major reasons: 1) a comprehensive understanding of the genetic consequences that arise from mutations to the SUMO pathways, with regards to DNA replication, will impact the development of assays for cancer diagnosis. 2) Identifying the molecular mechanism by which SUMO regulates DNA replication will lead to the development of new therapeutic interventions of human disease. Thus, in the proposed studies we will characterize the genetics and biochemistry of the SUMO pathways in the model organism S. cerevisiae. We will pursue the following specific aims: First, we will characterize the function of protein sumoylation during chromosomal DNA replication. Second, we will investigate the role of SUMO and ubiquitin in regulating DNA replication. And finally, we will study how reversible sumoylation of the DNA replisome is regulated. The ultimate goal is to understand how SUMO regulates DNA replication and how cells utilize this pathway to prevent genome rearrangements.

Public Health Relevance

Protein sumoylation, an evolutionarily conserved post-translational modification in eukaryotes, plays a major role in suppressing genome rearrangements, a major hallmark of cancer. The proposed project will investigate how the protein sumoylation pathways regulate chromosomal DNA replication to prevent the accumulation of DNA breaks, which can lead to genome rearrangements. Insights from our studies will contribute to understanding the genesis of cancer, leading to the development of new tools for cancer diagnostics as well as improved therapeutic strategies.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
2R01GM116897-06A1
Application #
9886800
Study Section
Molecular Genetics B Study Section (MGB)
Program Officer
Janes, Daniel E
Project Start
2015-09-30
Project End
2024-03-31
Budget Start
2020-04-01
Budget End
2021-03-31
Support Year
6
Fiscal Year
2020
Total Cost
Indirect Cost
Name
University of California, San Diego
Department
Other Basic Sciences
Type
Schools of Medicine
DUNS #
804355790
City
La Jolla
State
CA
Country
United States
Zip Code
92093
Liang, Jason; Li, Bin-Zhong; Tan, Alexander P et al. (2018) SUMO E3 ligase Mms21 prevents spontaneous DNA damage induced genome rearrangements. PLoS Genet 14:e1007250
de Albuquerque, Claudio Ponte; Suhandynata, Raymond T; Carlson, Christopher R et al. (2018) Binding to small ubiquitin-like modifier and the nucleolar protein Csm1 regulates substrate specificity of the Ulp2 protease. J Biol Chem 293:12105-12119
Local, Andrea; Huang, Hui; Albuquerque, Claudio P et al. (2018) Identification of H3K4me1-associated proteins at mammalian enhancers. Nat Genet 50:73-82
Gu, Yuchao; Albuquerque, Claudio P; Braas, Daniel et al. (2017) mTORC2 Regulates Amino Acid Metabolism in Cancer by Phosphorylation of the Cystine-Glutamate Antiporter xCT. Mol Cell 67:128-138.e7
Liang, Jason; Singh, Namit; Carlson, Christopher R et al. (2017) Recruitment of a SUMO isopeptidase to rDNA stabilizes silencing complexes by opposing SUMO targeted ubiquitin ligase activity. Genes Dev 31:802-815
de Albuquerque, Claudio Ponte; Liang, Jason; Gaut, Nathaniel James et al. (2016) Molecular Circuitry of the SUMO (Small Ubiquitin-like Modifier) Pathway in Controlling Sumoylation Homeostasis and Suppressing Genome Rearrangements. J Biol Chem 291:8825-35
Albuquerque, Claudio P; Yeung, Eyan; Ma, Shawn et al. (2015) A Chemical and Enzymatic Approach to Study Site-Specific Sumoylation. PLoS One 10:e0143810