Project description:Differential responses to stimuli can affect how cells succumb to disease. In yeast, DNA damage can create heterogeneous responses. To delineate how a response contributes to a cell's future behavior, we constructed a transcription-based memory circuit that detects DNA repair to isolate subpopulations with heritable damage responses. Strongly responsive cells show multigenerational effects, including growth defects and iron-associated gene expression. Less-responsive cells exhibit increased mutation frequencies but resume wild-type behavior. These two subpopulations remain distinct for multiple generations, indicating a transmissible memory of damage. Collectively, this work demonstrates the efficacy of using synthetic biology to define how environmental exposure contributes to distinct cell fates. Cells containing the HUG1 memory device (Burrill, 2011) were exposed to 0.3% EMS for 24 h and recovered for 36 h, at which point cells were sorted based on YFP expression, i.e. memory and non-memory cells. These two sorted populations were then grown for another 12 h, at which point transcriptional profiling was performed.
Project description:Differential responses to stimuli can affect how cells succumb to disease. In yeast, DNA damage can create heterogeneous responses. To delineate how a response contributes to a cell's future behavior, we constructed a transcription-based memory circuit that detects DNA repair to isolate subpopulations with heritable damage responses. Strongly responsive cells show multigenerational effects, including growth defects and iron-associated gene expression. Less-responsive cells exhibit increased mutation frequencies but resume wild-type behavior. These two subpopulations remain distinct for multiple generations, indicating a transmissible memory of damage. Collectively, this work demonstrates the efficacy of using synthetic biology to define how environmental exposure contributes to distinct cell fates.
Project description:A network governing DNA integrity was identified in yeast by a global genetic analysis of synthetic fitness or lethality defect (SFL) interactions. Within this network, multiple functional modules or mini-pathways were defined according to their common patterns of global SFL interactions and available protein-protein interaction information. Modules or genes involved in DNA replication, DNA replication checkpoint signaling, and oxidative stress response were identified as the major guardians against lethal spontaneous DNA damage, efficient repair of which requires the functions of the DNA damage checkpoint signaling and multiple DNA repair pathways. This genome-wide genetic interaction network also revealed potential roles of a number of genes and modules in mitotic DNA replication and maintenance of genomic stability. These include DIA2, NPT1, HST3, HST4, and the CSM1/LRS4 module (CSM1m). Likewise, the CTF18 module (CTF18m), previously implicated in sister chromatid cohesion, was found to participate in the DNA replication checkpoint. Keywords: dose response
Project description:In the yeast Saccharomyces cerevisiae, cleavage factor I (CFI) and cleavage and polyadenylation factor (CPF) build the core of the transcription termination machinery. CFI comprises the Rna14, Rna15, Pcf11, and Clp1 proteins, as well as the associated Hrp5 RNA-binding protein. We found that CFI participates in the DNA damage response and that rna14-1 shows synthetic growth defects with mutants of different repair pathways, including homologous recombination, non-homologous end joining, post replicative repair, mismatch repair, and nucleotide excision repair, implicating that impaired RNAPII termination and 3’-end processing decreases the cellular tolerance for DNA damage. Beyond replication progression defects, we found that bypass of the G1/S checkpoint in rna14-1 cells leads to synthetic sickness, accumulation of phosphorylated H2A, as well as increase in Rad52-foci and in recombination. Our data provide evidence that CFI dysfunction impairs RNAPII turnover, leading to replication hindrance and lower tolerance to exogenous DNA damage. These findings underscore the importance of coordination between transcription termination, DNA repair and replication in the maintenance of genomic stability.
Project description:In the yeast Saccharomyces cerevisiae, cleavage factor I (CFI) and cleavage and polyadenylation factor (CPF) build the core of the transcription termination machinery. CFI comprises the Rna14, Rna15, Pcf11, and Clp1 proteins, as well as the associated Hrp5 RNA-binding protein. We found that CFI participates in the DNA damage response and that rna14-1 shows synthetic growth defects with mutants of different repair pathways, including homologous recombination, non-homologous end joining, post replicative repair, mismatch repair, and nucleotide excision repair, implicating that impaired RNAPII termination and 3â-end processing decreases the cellular tolerance for DNA damage. Beyond replication progression defects, we found that bypass of the G1/S checkpoint in rna14-1 cells leads to synthetic sickness, accumulation of phosphorylated H2A, as well as increase in Rad52-foci and in recombination. Our data provide evidence that CFI dysfunction impairs RNAPII turnover, leading to replication hindrance and lower tolerance to exogenous DNA damage. These findings underscore the importance of coordination between transcription termination, DNA repair and replication in the maintenance of genomic stability. S. cerevisiae strains were grown in YPAD liquid culture at 30°C, total RNA was isolated and hybridized on Affymetrix microarrays.
Project description:Cells respond heterogeneously to DNA damage. We engineered genetic circuits to detect differential responses in a population that persist for many days post-stimulus. We used microarrays to compare memory and non-memory subpopulations 3 days after DNA damage or doxycycline exposure. MD12/p53R2-RE and MD10/TetOx2 cells were either exposed to UV (10uJ/m^2) or doxycycline (1 ug/mL, 24 hours) and allowed to recover 3 days before sortng of memory and non-memory cells and RNA extraction. Two replicates were submitted for each condition (UV memory, UV non-memory, dox memory, dox non-memory)