ATR and ATM play both distinct and additive roles in response to ionizing radiation

Abstract

SummaryThe ATR and ATM protein kinases are known to be involved in a wide variety of responses to DNA damage. The Arabidopsis thaliana genome includes both ATR and ATM orthologs, and plants with null alleles of these genes are viable. Arabidopsis atr and atm mutants display hypersensitivity to c-irradiation. To further characterize the roles of ATM and ATR in response to ionizing radiation, we performed a short-term global transcription analysis in wild-type and mutant lines. We found that hundreds of genes are upregulated in response to cirradiation, and that the induction of virtually all of these genes is dependent on ATM, but not ATR. The transcript of CYCB1;1 is unique among the cyclin transcripts in being rapidly and powerfully upregulated in response to ionizing radiation, while other G 2 -associated transcripts are suppressed. We found that both ATM and ATR contribute to the induction of a CYCB1;1:GUS fusion by IR, but only ATR is required for the persistence of this response. We propose that this upregulation of CYCB1;1 does not reflect the accumulation of cells in G 2 , but instead reflects a still unknown role for this cyclin in DNA damage response.

The plant‐specific CDKB 1‐ CYCB 1 complex mediates homologous recombination repair in Arabidopsis

“…Previously, it was found that CYCB1;1 upregulation depends on ATM and SOG1 (Culligan et al , 2006; Yoshiyama et al , 2009). To test therefore whether CYCB1;1 and CDKB1s are directly regulated by SOG1, we performed ChIP experiments with plants expressing a tagged SOG1 version grown on cisplatin.…”

The Recombinases DMC1 and RAD51 Are Functionally and Spatially Separated during Meiosis in Arabidopsis

“…Arabidopsis thaliana atm mutants display chromosomal fragmentation in most meiocytes, leading to reduced fertility (Garcia et al, 2003). atr mutant plants, by contrast, are fully fertile, but atm atr double mutants are completely sterile, because of severe chromatin fragmentation (Culligan et al, 2004;Culligan et al, 2006;Culligan and Britt, 2008).…”

SUPPRESSOR OF GAMMA RESPONSE1 Links DNA Damage Response to Organ Regeneration

“…ATM (Yoshiyama et al, 2013) and inferably ATR (Furukawa et al, 2010;Yoshiyama et al, 2009) can phosphoactivate the transcription factor SOG1, as well as other proteins, in plant cells (Roitinger et al, 2015;Yoshiyama et al, 2013). Once activated, SOG1 transcriptionally induces various functional classes of DDR genes (Yoshiyama et al, 2009;Missirian et al, 2014;Ricaud et al, 2007); SOG1 induces a robust set of .100 transcripts by $4-fold within 1.5 h in response to 100 Gy IR (Culligan et al, 2006;Furukawa et al, 2010). SOG1 has a known role in transcriptionally inhibiting cell cycle progression in response to DNA damage (Preuss and Britt, 2003;Yoshiyama et al, 2009).…”

“…A plant cell's response to DNA damage first involves the DSB-detecting protein kinase ATM (AtaxiaTelangiectasia-Mutated) or the detector of stalled replication forks ATR (Ataxia Telangiectasia Mutated and Rad3-related protein; Culligan et al, 2006;Furukawa et al, 2010). ATM (Yoshiyama et al, 2013) and inferably ATR (Furukawa et al, 2010;Yoshiyama et al, 2009) can phosphoactivate the transcription factor SOG1, as well as other proteins, in plant cells (Roitinger et al, 2015;Yoshiyama et al, 2013).…”