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The amino-terminal tails of histones H2A and H3 coordinate efficient base excision repair, DNA damage signaling and postreplication repair in Saccharomyces cerevisiae.

Meas R, Smerdon MJ, Wyrick JJ - Nucleic Acids Res. (2015)

Bottom Line: Combinatorial deletions reveal that the H2A and H3 N-tails are important for the removal of MMS-induced DNA lesions due to their role in regulating the basal and MMS-induced expression of DNA glycosylase Mag1.We further show that the H3 N-tail functions in the Rad9/Rad53 DNA damage signaling pathway, but this function does not appear to be the primary cause of MMS sensitivity of the double tailless mutants.We observed increased levels of ubiquitylated PCNA and significantly lower mutation frequency in the tailless H2A/H3 mutant, indicating a defect in postreplication repair.

View Article: PubMed Central - PubMed

Affiliation: School of Molecular Biosciences, Washington State University, Pullman, WA 99164-7520, USA.

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The N-tails of H2A and H3 are epistatic to RAD18. (A) Epistasis studies of (i) N-tail deletion mutants combinatorially deleted for (ii) MAG1, (iii) REV3, (iv) RAD5 and (v) RAD18. (B) Epistasis study of N-tail deletion mutants combinatorially deleted for RAD52. (C) MMS survival assay of WT and N-tail mutants (solid lines) and the N-tail mutants combinatorially deleted for RAD18 (dashed lines). (D) Growth curves of the cells in (C) in the absence of MMS. (E) Western blot of PCNA9myc in WT and N-tail mutants before UV exposure and after a 1 h recovery in YPD following 100 J/m2 of UV irradiation. GAPDH is used as the loading control. rad6Δ serves as a negative control for PCNA ubiquitylation. (F) Quantifications of (E) by normalizing (PCNA9myc-ub)/(PCNA9myc-total) and (PCNA9myc-ub2)/(PCNA9myc-total) to WT. Error bars indicate standard deviations from three independent experiments.
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Figure 6: The N-tails of H2A and H3 are epistatic to RAD18. (A) Epistasis studies of (i) N-tail deletion mutants combinatorially deleted for (ii) MAG1, (iii) REV3, (iv) RAD5 and (v) RAD18. (B) Epistasis study of N-tail deletion mutants combinatorially deleted for RAD52. (C) MMS survival assay of WT and N-tail mutants (solid lines) and the N-tail mutants combinatorially deleted for RAD18 (dashed lines). (D) Growth curves of the cells in (C) in the absence of MMS. (E) Western blot of PCNA9myc in WT and N-tail mutants before UV exposure and after a 1 h recovery in YPD following 100 J/m2 of UV irradiation. GAPDH is used as the loading control. rad6Δ serves as a negative control for PCNA ubiquitylation. (F) Quantifications of (E) by normalizing (PCNA9myc-ub)/(PCNA9myc-total) and (PCNA9myc-ub2)/(PCNA9myc-total) to WT. Error bars indicate standard deviations from three independent experiments.

Mentions: We performed epistasis studies to genetically identify which DNA damage response pathways are important for the MMS sensitivity of the tH2A:tH3 mutant. First, we tested epistasis for the BER pathway by examining double mutants in which the MAG1 gene was deleted in the tH2A, tH3, and tH2A:tH3 mutant strains. As shown in Figure 6A.ii, the deletion of MAG1 with any of the tail deletion combinations showed increased MMS sensitivity over that of the mag1Δ mutant alone, indicating that histone tailless mutants are not epistatic to the BER pathway. These data confirm that BER is not the only MMS-response pathway affected when the N-tails of H2A and H3 are deleted.


The amino-terminal tails of histones H2A and H3 coordinate efficient base excision repair, DNA damage signaling and postreplication repair in Saccharomyces cerevisiae.

Meas R, Smerdon MJ, Wyrick JJ - Nucleic Acids Res. (2015)

The N-tails of H2A and H3 are epistatic to RAD18. (A) Epistasis studies of (i) N-tail deletion mutants combinatorially deleted for (ii) MAG1, (iii) REV3, (iv) RAD5 and (v) RAD18. (B) Epistasis study of N-tail deletion mutants combinatorially deleted for RAD52. (C) MMS survival assay of WT and N-tail mutants (solid lines) and the N-tail mutants combinatorially deleted for RAD18 (dashed lines). (D) Growth curves of the cells in (C) in the absence of MMS. (E) Western blot of PCNA9myc in WT and N-tail mutants before UV exposure and after a 1 h recovery in YPD following 100 J/m2 of UV irradiation. GAPDH is used as the loading control. rad6Δ serves as a negative control for PCNA ubiquitylation. (F) Quantifications of (E) by normalizing (PCNA9myc-ub)/(PCNA9myc-total) and (PCNA9myc-ub2)/(PCNA9myc-total) to WT. Error bars indicate standard deviations from three independent experiments.
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Figure 6: The N-tails of H2A and H3 are epistatic to RAD18. (A) Epistasis studies of (i) N-tail deletion mutants combinatorially deleted for (ii) MAG1, (iii) REV3, (iv) RAD5 and (v) RAD18. (B) Epistasis study of N-tail deletion mutants combinatorially deleted for RAD52. (C) MMS survival assay of WT and N-tail mutants (solid lines) and the N-tail mutants combinatorially deleted for RAD18 (dashed lines). (D) Growth curves of the cells in (C) in the absence of MMS. (E) Western blot of PCNA9myc in WT and N-tail mutants before UV exposure and after a 1 h recovery in YPD following 100 J/m2 of UV irradiation. GAPDH is used as the loading control. rad6Δ serves as a negative control for PCNA ubiquitylation. (F) Quantifications of (E) by normalizing (PCNA9myc-ub)/(PCNA9myc-total) and (PCNA9myc-ub2)/(PCNA9myc-total) to WT. Error bars indicate standard deviations from three independent experiments.
Mentions: We performed epistasis studies to genetically identify which DNA damage response pathways are important for the MMS sensitivity of the tH2A:tH3 mutant. First, we tested epistasis for the BER pathway by examining double mutants in which the MAG1 gene was deleted in the tH2A, tH3, and tH2A:tH3 mutant strains. As shown in Figure 6A.ii, the deletion of MAG1 with any of the tail deletion combinations showed increased MMS sensitivity over that of the mag1Δ mutant alone, indicating that histone tailless mutants are not epistatic to the BER pathway. These data confirm that BER is not the only MMS-response pathway affected when the N-tails of H2A and H3 are deleted.

Bottom Line: Combinatorial deletions reveal that the H2A and H3 N-tails are important for the removal of MMS-induced DNA lesions due to their role in regulating the basal and MMS-induced expression of DNA glycosylase Mag1.We further show that the H3 N-tail functions in the Rad9/Rad53 DNA damage signaling pathway, but this function does not appear to be the primary cause of MMS sensitivity of the double tailless mutants.We observed increased levels of ubiquitylated PCNA and significantly lower mutation frequency in the tailless H2A/H3 mutant, indicating a defect in postreplication repair.

View Article: PubMed Central - PubMed

Affiliation: School of Molecular Biosciences, Washington State University, Pullman, WA 99164-7520, USA.

Show MeSH
Related in: MedlinePlus