scholarly journals The SFP1 Gene Product of Saccharomyces cerevisiae Regulates G2/M Transitions During the Mitotic Cell Cycle and DNA-Damage Response

Genetics ◽  
1998 ◽  
Vol 150 (4) ◽  
pp. 1419-1428
Author(s):  
Zhiheng Xu ◽  
David Norris

Abstract In eukaryotic cells, checkpoint pathways arrest cell-cycle progression if a particular event has failed to complete appropriately or if an important intracellular structure is defective or damaged. Saccharomyces cerevisiae strains that lack the SFP1 gene fail to arrest at the G2 DNA-damage checkpoint in response to genomic injury, but maintain their ability to arrest at the replication and spindle-assembly checkpoints. sfp1Δ mutants are characterized by a premature entrance into mitosis during a normal (undamaged) cell cycle, while strains that overexpress Sfp1p exhibit delays in G2. Sfp1p therefore acts as a repressor of the G2/M transition, both in the normal cell cycle and in the G2 checkpoint pathway. Sfp1 is a nuclear protein with two Cys2His2 zinc-finger domains commonly found in transcription factors. We propose that Sfp1p regulates the expression of gene products involved in the G2/M transition during the mitotic cell cycle and the DNA-damage response. In support of this model, overexpression of Sfp1p induces the expression of the PDS1 gene, which is known to encode a protein that regulates the G2 checkpoint.

2020 ◽  
Vol 40 (5) ◽  
pp. 2449-2456
Author(s):  
ALEXANDRA KANELLOU ◽  
NICKOLAOS NIKIFOROS GIAKOUMAKIS ◽  
ANDREAS PANAGOPOULOS ◽  
SPYRIDON CHAMPERIS TSANIRAS ◽  
ZOI LYGEROU

Open Biology ◽  
2015 ◽  
Vol 5 (3) ◽  
pp. 140156 ◽  
Author(s):  
Didier J. Colin ◽  
Karolina O. Hain ◽  
Lindsey A. Allan ◽  
Paul R. Clarke

Anti-cancer drugs that disrupt mitosis inhibit cell proliferation and induce apoptosis, although the mechanisms of these responses are poorly understood. Here, we characterize a mitotic stress response that determines cell fate in response to microtubule poisons. We show that mitotic arrest induced by these drugs produces a temporally controlled DNA damage response (DDR) characterized by the caspase-dependent formation of γH2AX foci in non-apoptotic cells. Following exit from a delayed mitosis, this initial response results in activation of DDR protein kinases, phosphorylation of the tumour suppressor p53 and a delay in subsequent cell cycle progression. We show that this response is controlled by Mcl-1, a regulator of caspase activation that becomes degraded during mitotic arrest. Chemical inhibition of Mcl-1 and the related proteins Bcl-2 and Bcl-x L by a BH3 mimetic enhances the mitotic DDR, promotes p53 activation and inhibits subsequent cell cycle progression. We also show that inhibitors of DDR protein kinases as well as BH3 mimetics promote apoptosis synergistically with taxol (paclitaxel) in a variety of cancer cell lines. Our work demonstrates the role of mitotic DNA damage responses in determining cell fate in response to microtubule poisons and BH3 mimetics, providing a rationale for anti-cancer combination chemotherapies.


2017 ◽  
Author(s):  
Filippo Casonil ◽  
Laura Crocil ◽  
Camilla Bosonel ◽  
Roberta D’Ambrosio ◽  
Aurora Badaloni ◽  
...  

ABSTRACTNeurogenesis is a tightly regulated process whose success depends on the ability to balance the expansion/maintenance of an undifferentiated neural progenitor pool with the precisely timed birth of sequential generations of neurons. The Zfp423 gene encodes a 30-Zn-finger transcription factor (TF) that acts as a scaffold in the assembly of complex transcriptional and cellular machineries regulating neural development. While null mutants for Zfp423 feature a severe cerebellar hypoplasia, the underlying mechanism is only partially characterized. Mutations of the human ortholog ZNF423 have been identified in patients carrying cerebellar vermis hypoplasia (CVH) or Joubert Syndrome (JS), associated with other signs of classical ciliopathy outside the central nervous system (CNS). ZNF423 also plays a role in the DNA damage response (DDR). To further characterize the role of ZFP423 in cerebellar neurogenesis, with a focus on Purkinje cells (PC) development, we analyzed two previously undescribed mutant mouse lines carrying allelic in-frame deletions of the corresponding gene, selectively affecting two functionally characterized protein-protein interaction domains, affecting zinc (Zn) fingers 9-20 or 28-30. Some phenotypic defects are allele specific: Zfp423Δ9-20/Δ9-20 mutants exhibit a depletion of the OLIG2+ PC progenitor pool in the cerebellar ventricular zone (VZ). In these mutants, M-phase progenitors display changes in spindle orientation indicative of a precocious switch from symmetric to asymmetric cell division. Conversely, the Zfp423Δ28-30/Δ28-30 primordium displays a sharp decrease in the expression of PC differentiation markers, including CORL2, despite an abundance of cycling PC progenitors. Moreover, and importantly, in both mutants VZ progenitor cell cycle progression is remarkably affected, and factors involved in the DDR are substantially upregulated in the VZ and in postmitotic precursors alike. Our in vivo evidence sheds light on the domain-specific roles played by ZFP423 in different aspects of PC progenitor development, and at the same time supports the emerging notion that an impaired DNA damage response may be a key factor in the pathogenesis of JS and other ciliopathies.


2021 ◽  
Author(s):  
Swathy Babu ◽  
Yuki Takeuchi ◽  
Ichiro Masai

Btg3-associated nuclear protein (Banp) was originally identified as a nuclear matrix-associated protein and it functions as a tumor suppressor. At molecular level, Banp regulates transcription of metabolic genes via a CGCG-containing motif called the Banp motif. However, its physiological roles in embryonic development are unknown. Here we report that Banp is indispensable for DNA damage response and chromosome segregation during mitosis. Zebrafish banp mutants show mitotic arrest and apoptosis in developing retina. We found that DNA replication stress and tp53-dependent DNA damage responses were activated to induce apoptosis in banp mutants, suggesting that Banp is required for integrity of DNA replication and DNA damage repair. Furthermore, in banp mutants, chromosome segregation was not smoothly processed from prometaphase to anaphase, leading to a prolonged M-phase. Our RNA- and ATAC-sequencing identified 31 candidates for direct Banp target genes that carry the Banp motif. Interestingly, two chromosome segregation regulators, cenpt and ncapg, are included in this list. Thus, Banp directly regulates transcription of cenpt and ncapg to promote chromosome segregation during mitosis. Our findings provide the first in vivo evidence that Banp is required for cell-cycle progression and cell survival by regulating DNA damage responses and chromosome segregation during mitosis.


2020 ◽  
Author(s):  
Konstantinos Sousounis ◽  
Donald M Bryant ◽  
Jose Martinez Fernandez ◽  
Samuel S Eddy ◽  
Stephanie L Tsai ◽  
...  

1990 ◽  
Vol 10 (6) ◽  
pp. 3256-3257
Author(s):  
K Madura ◽  
S Prakash

The expression of the RAD2 gene of Saccharomyces cerevisiae is elevated upon DNA damage. Here, we show that RAD2 transcript levels also rise approximately eightfold during meiosis but remain constant during the mitotic cell cycle. The period of maximal RAD2 mRNA accumulation during meiosis is consistent with a possible role of RAD2 in a late stage of recombination, in mismatch repair of heteroduplexes, or both.


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