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NatB domain-containing CRA-1 antagonizes hydrolase ACER-1 linking acetyl-CoA metabolism to the initiation of recombination during C. elegans meiosis.

Gao J, Kim HM, Elia AE, Elledge SJ, Colaiácovo MP - PLoS Genet. (2015)

Bottom Line: Moreover, perturbations to global histone acetylation levels are accompanied by changes in the frequency of DSB formation in C. elegans.CRA-1 is in turn negatively regulated by XND-1, an AT-hook containing protein.We propose that this newly defined protein network links acetyl-CoA metabolism to meiotic DSB formation via modulation of global histone acetylation.

View Article: PubMed Central - PubMed

Affiliation: Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America.

ABSTRACT
The formation of DNA double-strand breaks (DSBs) must take place during meiosis to ensure the formation of crossovers, which are required for accurate chromosome segregation, therefore avoiding aneuploidy. However, DSB formation must be tightly regulated to maintain genomic integrity. How this regulation operates in the context of different chromatin architectures and accessibility, and how it is linked to metabolic pathways, is not understood. We show here that global histone acetylation levels undergo changes throughout meiotic progression. Moreover, perturbations to global histone acetylation levels are accompanied by changes in the frequency of DSB formation in C. elegans. We provide evidence that the regulation of histone acetylation requires CRA-1, a NatB domain-containing protein homologous to human NAA25, which controls the levels of acetyl-Coenzyme A (acetyl-CoA) by antagonizing ACER-1, a previously unknown and conserved acetyl-CoA hydrolase. CRA-1 is in turn negatively regulated by XND-1, an AT-hook containing protein. We propose that this newly defined protein network links acetyl-CoA metabolism to meiotic DSB formation via modulation of global histone acetylation.

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Time course analysis of DSB levels.(A) Diagram of a C. elegans germline showing the position of the zones scored for a time course analysis of RAD-51 foci levels. PMT (premeiotic tip); zones 1–5 correspond to: transition zone (1), early (2), mid (3–4), and late (5) pachytene stages of prophase I. (B) Time course analysis of RAD-51 foci levels in the indicated genotypes. Gonads were co-stained with an anti-RAD-51 antibody and DAPI. The mean number ± SEM of RAD-51 foci scored per nucleus is indicated for nuclei in the premeiotic tip (PMT) and five zones of meiotic prophase: TZ, transition zone; EP, early pachytene; MP, mid-pachytene; LP, late pachytene. (C) Gonads from wild type and xnd-1 mutants were immunostained with an anti-RAD-51 antibody (red) and DNA was stained with DAPI (blue). Bar, 30 μm. Arrows show the position of meiotic entry. Asterisks show the position where levels of RAD-51 foci peak along the gonads in the different genotypes, and these regions are shown at a higher-magnification in the insets. Bar, 5 μm. (D) Graph shows the levels of RAD-51 foci observed along the germline in the indicated genotypes, all in a rad-54 background where DSB-bound RAD-51 is “trapped”. Data represent mean number and SEM of RAD-51 foci per nucleus for premeiotic tip (PMT) and three zones of the germline. * P<0.001 by the two-tailed t test, 95% C.I.
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pgen.1005029.g004: Time course analysis of DSB levels.(A) Diagram of a C. elegans germline showing the position of the zones scored for a time course analysis of RAD-51 foci levels. PMT (premeiotic tip); zones 1–5 correspond to: transition zone (1), early (2), mid (3–4), and late (5) pachytene stages of prophase I. (B) Time course analysis of RAD-51 foci levels in the indicated genotypes. Gonads were co-stained with an anti-RAD-51 antibody and DAPI. The mean number ± SEM of RAD-51 foci scored per nucleus is indicated for nuclei in the premeiotic tip (PMT) and five zones of meiotic prophase: TZ, transition zone; EP, early pachytene; MP, mid-pachytene; LP, late pachytene. (C) Gonads from wild type and xnd-1 mutants were immunostained with an anti-RAD-51 antibody (red) and DNA was stained with DAPI (blue). Bar, 30 μm. Arrows show the position of meiotic entry. Asterisks show the position where levels of RAD-51 foci peak along the gonads in the different genotypes, and these regions are shown at a higher-magnification in the insets. Bar, 5 μm. (D) Graph shows the levels of RAD-51 foci observed along the germline in the indicated genotypes, all in a rad-54 background where DSB-bound RAD-51 is “trapped”. Data represent mean number and SEM of RAD-51 foci per nucleus for premeiotic tip (PMT) and three zones of the germline. * P<0.001 by the two-tailed t test, 95% C.I.

Mentions: We next assessed how changes in global histone acetylation might affect the timing of meiotic DSB formation. Immunostaining of cra-1 mutant germlines had previously shown elevated levels of RAD-51 foci upon entrance into pachytene that remained elevated throughout late pachytene compared to wild type ([30]; Fig. 4A-B). Analysis of xnd-1 mutants, where H2AK5ac is increased, revealed an increase in the levels of RAD-51 foci at transition zone and early pachytene (zones 1 and 2, respectively) compared to wild type (Fig. 4A-B). Moreover, levels of RAD-51 foci peaked at transition zone in xnd-1 compared to early- to mid-pachytene in wild type (Fig. 4C). This observation suggests that DSBs might be formed earlier in xnd-1 mutants compared to wild type, consistent with [37]. However, elevated levels of RAD-51 foci are still observed during early meiotic prophase (zones 1 and 2) in xnd-1;cra-1(RNAi) mutants. Moreover, TSA treatment does not affect the kinetics of RAD-51 foci along meiotic prophase compared to the control (Fig. 4B). These data indicate that changes in global histone acetylation do not affect the timing of DSB formation, which instead might be regulated by a separate function exerted by XND-1.


NatB domain-containing CRA-1 antagonizes hydrolase ACER-1 linking acetyl-CoA metabolism to the initiation of recombination during C. elegans meiosis.

Gao J, Kim HM, Elia AE, Elledge SJ, Colaiácovo MP - PLoS Genet. (2015)

Time course analysis of DSB levels.(A) Diagram of a C. elegans germline showing the position of the zones scored for a time course analysis of RAD-51 foci levels. PMT (premeiotic tip); zones 1–5 correspond to: transition zone (1), early (2), mid (3–4), and late (5) pachytene stages of prophase I. (B) Time course analysis of RAD-51 foci levels in the indicated genotypes. Gonads were co-stained with an anti-RAD-51 antibody and DAPI. The mean number ± SEM of RAD-51 foci scored per nucleus is indicated for nuclei in the premeiotic tip (PMT) and five zones of meiotic prophase: TZ, transition zone; EP, early pachytene; MP, mid-pachytene; LP, late pachytene. (C) Gonads from wild type and xnd-1 mutants were immunostained with an anti-RAD-51 antibody (red) and DNA was stained with DAPI (blue). Bar, 30 μm. Arrows show the position of meiotic entry. Asterisks show the position where levels of RAD-51 foci peak along the gonads in the different genotypes, and these regions are shown at a higher-magnification in the insets. Bar, 5 μm. (D) Graph shows the levels of RAD-51 foci observed along the germline in the indicated genotypes, all in a rad-54 background where DSB-bound RAD-51 is “trapped”. Data represent mean number and SEM of RAD-51 foci per nucleus for premeiotic tip (PMT) and three zones of the germline. * P<0.001 by the two-tailed t test, 95% C.I.
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pgen.1005029.g004: Time course analysis of DSB levels.(A) Diagram of a C. elegans germline showing the position of the zones scored for a time course analysis of RAD-51 foci levels. PMT (premeiotic tip); zones 1–5 correspond to: transition zone (1), early (2), mid (3–4), and late (5) pachytene stages of prophase I. (B) Time course analysis of RAD-51 foci levels in the indicated genotypes. Gonads were co-stained with an anti-RAD-51 antibody and DAPI. The mean number ± SEM of RAD-51 foci scored per nucleus is indicated for nuclei in the premeiotic tip (PMT) and five zones of meiotic prophase: TZ, transition zone; EP, early pachytene; MP, mid-pachytene; LP, late pachytene. (C) Gonads from wild type and xnd-1 mutants were immunostained with an anti-RAD-51 antibody (red) and DNA was stained with DAPI (blue). Bar, 30 μm. Arrows show the position of meiotic entry. Asterisks show the position where levels of RAD-51 foci peak along the gonads in the different genotypes, and these regions are shown at a higher-magnification in the insets. Bar, 5 μm. (D) Graph shows the levels of RAD-51 foci observed along the germline in the indicated genotypes, all in a rad-54 background where DSB-bound RAD-51 is “trapped”. Data represent mean number and SEM of RAD-51 foci per nucleus for premeiotic tip (PMT) and three zones of the germline. * P<0.001 by the two-tailed t test, 95% C.I.
Mentions: We next assessed how changes in global histone acetylation might affect the timing of meiotic DSB formation. Immunostaining of cra-1 mutant germlines had previously shown elevated levels of RAD-51 foci upon entrance into pachytene that remained elevated throughout late pachytene compared to wild type ([30]; Fig. 4A-B). Analysis of xnd-1 mutants, where H2AK5ac is increased, revealed an increase in the levels of RAD-51 foci at transition zone and early pachytene (zones 1 and 2, respectively) compared to wild type (Fig. 4A-B). Moreover, levels of RAD-51 foci peaked at transition zone in xnd-1 compared to early- to mid-pachytene in wild type (Fig. 4C). This observation suggests that DSBs might be formed earlier in xnd-1 mutants compared to wild type, consistent with [37]. However, elevated levels of RAD-51 foci are still observed during early meiotic prophase (zones 1 and 2) in xnd-1;cra-1(RNAi) mutants. Moreover, TSA treatment does not affect the kinetics of RAD-51 foci along meiotic prophase compared to the control (Fig. 4B). These data indicate that changes in global histone acetylation do not affect the timing of DSB formation, which instead might be regulated by a separate function exerted by XND-1.

Bottom Line: Moreover, perturbations to global histone acetylation levels are accompanied by changes in the frequency of DSB formation in C. elegans.CRA-1 is in turn negatively regulated by XND-1, an AT-hook containing protein.We propose that this newly defined protein network links acetyl-CoA metabolism to meiotic DSB formation via modulation of global histone acetylation.

View Article: PubMed Central - PubMed

Affiliation: Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America.

ABSTRACT
The formation of DNA double-strand breaks (DSBs) must take place during meiosis to ensure the formation of crossovers, which are required for accurate chromosome segregation, therefore avoiding aneuploidy. However, DSB formation must be tightly regulated to maintain genomic integrity. How this regulation operates in the context of different chromatin architectures and accessibility, and how it is linked to metabolic pathways, is not understood. We show here that global histone acetylation levels undergo changes throughout meiotic progression. Moreover, perturbations to global histone acetylation levels are accompanied by changes in the frequency of DSB formation in C. elegans. We provide evidence that the regulation of histone acetylation requires CRA-1, a NatB domain-containing protein homologous to human NAA25, which controls the levels of acetyl-Coenzyme A (acetyl-CoA) by antagonizing ACER-1, a previously unknown and conserved acetyl-CoA hydrolase. CRA-1 is in turn negatively regulated by XND-1, an AT-hook containing protein. We propose that this newly defined protein network links acetyl-CoA metabolism to meiotic DSB formation via modulation of global histone acetylation.

Show MeSH
Related in: MedlinePlus