DNA methylation in Caulobacter and other Alphaproteobacteria during cell cycle progression

2014 ◽  
Vol 22 (9) ◽  
pp. 528-535 ◽  
Author(s):  
Saswat S. Mohapatra ◽  
Antonella Fioravanti ◽  
Emanuele G. Biondi
2020 ◽  
Author(s):  
Jennifer L. Kernan ◽  
Raquel C. Martinez-Chacin ◽  
Xianxi Wang ◽  
Rochelle L. Tiedemann ◽  
Thomas Bonacci ◽  
...  

AbstractThe Anaphase-Promoting Complex/Cyclosome (APC/C) is an E3 ubiquitin ligase and critical regulator of cell cycle progression. Despite its vital role, it has remained challenging to globally map APC/C substrates. By combining orthogonal features of known substrates, we predicted APC/C substrates in silico. This analysis identified many known substrates and suggested numerous candidates. Unexpectedly, chromatin regulatory proteins are enriched among putative substrates and we show that several chromatin proteins bind APC/C, oscillate during the cell cycle and are degraded following APC/C activation, consistent with being direct APC/C substrates. Additional analysis revealed detailed mechanisms of ubiquitylation for UHRF1, a key chromatin regulator involved in histone ubiquitylation and DNA methylation maintenance. Disrupting UHRF1 degradation at mitotic exit accelerates G1-phase cell cycle progression and perturbs global DNA methylation patterning in the genome. We conclude that APC/C coordinates crosstalk between cell cycle and chromatin regulatory proteins. This has potential consequences in normal cell physiology, where the chromatin environment changes depending on proliferative state, as well as in disease.


PLoS Biology ◽  
2020 ◽  
Vol 18 (12) ◽  
pp. e3000975
Author(s):  
Jennifer L. Franks ◽  
Raquel C. Martinez-Chacin ◽  
Xianxi Wang ◽  
Rochelle L. Tiedemann ◽  
Thomas Bonacci ◽  
...  

The anaphase-promoting complex/cyclosome (APC/C) is an E3 ubiquitin ligase and critical regulator of cell cycle progression. Despite its vital role, it has remained challenging to globally map APC/C substrates. By combining orthogonal features of known substrates, we predicted APC/C substrates in silico. This analysis identified many known substrates and suggested numerous candidates. Unexpectedly, chromatin regulatory proteins are enriched among putative substrates, and we show experimentally that several chromatin proteins bind APC/C, oscillate during the cell cycle, and are degraded following APC/C activation, consistent with being direct APC/C substrates. Additional analysis revealed detailed mechanisms of ubiquitylation for UHRF1, a key chromatin regulator involved in histone ubiquitylation and DNA methylation maintenance. Disrupting UHRF1 degradation at mitotic exit accelerates G1-phase cell cycle progression and perturbs global DNA methylation patterning in the genome. We conclude that APC/C coordinates crosstalk between cell cycle and chromatin regulatory proteins. This has potential consequences in normal cell physiology, where the chromatin environment changes depending on proliferative state, as well as in disease.


2018 ◽  
Author(s):  
Xiaofeng Zhou ◽  
Lucy Shapiro

AbstractN6-adenine methylation catalyzed by the DNA methyltransferase CcrM is an essential epigenetic event of theCaulobactercell cycle. Limiting CcrM to a specific time period during the cell cycle relies on temporal control ofccrMtranscription and CcrM proteolysis. We investigated how Lon, a protease from AAA+ superfamily conserved from bacteria to humans, temporally degrades CcrM to maintain differential chromosomal methylation state, thereby regulating transcription factor synthesis and enabling cell cycle progression. We demonstrate that CcrM degradation by Lon requires DNA as an adaptor for robust proteolysis. Lon, a DNA-bound protein, is constitutively active throughout the cell cycle, but allows CcrM mediated DNA methylation only when CcrM is transcribed and translated upon completion of DNA replication. An additional mechanism to limit CcrM activity to a narrow window of the cell cycle is its sequestration to the pole of the progeny stalked cell, which prevents physical contact with DNA-bound Lon. Thus, we have provided evidence for a novel mechanism for substrate selection by the Lon protease, providing robust cell cycle control mediated by DNA methylation.


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