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An increase in mitochondrial DNA promotes nuclear DNA replication in yeast.

Blank HM, Li C, Mueller JE, Bogomolnaya LM, Bryk M, Polymenis M - PLoS Genet. (2008)

Bottom Line: The Sir2p NAD+-dependent de-acetylase antagonizes this mitochondrial role.We found that cells with increased mitochondrial DNA have reduced Sir2p levels bound at origins of DNA replication in the nucleus, accompanied with increased levels of K9, K14-acetylated histone H3 at those origins.They also suggest that cellular metabolism may impact on chromatin modifications to regulate the activity of origins of DNA replication.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America.

ABSTRACT
Coordination between cellular metabolism and DNA replication determines when cells initiate division. It has been assumed that metabolism only plays a permissive role in cell division. While blocking metabolism arrests cell division, it is not known whether an up-regulation of metabolic reactions accelerates cell cycle transitions. Here, we show that increasing the amount of mitochondrial DNA accelerates overall cell proliferation and promotes nuclear DNA replication, in a nutrient-dependent manner. The Sir2p NAD+-dependent de-acetylase antagonizes this mitochondrial role. We found that cells with increased mitochondrial DNA have reduced Sir2p levels bound at origins of DNA replication in the nucleus, accompanied with increased levels of K9, K14-acetylated histone H3 at those origins. Our results demonstrate an active role of mitochondrial processes in the control of cell division. They also suggest that cellular metabolism may impact on chromatin modifications to regulate the activity of origins of DNA replication.

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Cells over-expressing ABF2 have less Sir2p and higher levels of K9, K14 acetylated histone H3 at the rDNA ARS elements.A, Immunoblot showing that the level of Sir2p is not altered in whole cell extracts from cells over-expressing ABF2. The same blot was stained with Ponceau, to indicate loading. Loading was also evaluated from the same samples, with an anti-Cdc28p antibody. B, ChIP experiments analyzed by real-time PCR show that the level of Sir2p (%IP) at the rDNA ARS elements is reduced in 3XABF2+ cells. Part of one rDNA repeat is shown above indicating the location of the rDNA ARS elements, the primers used (primer pairs 20, 21, 22); the nontranscribed spacer (NTS); and the 35S and 5S rRNA genes. The values shown in the bar graph are the average %IPs (±s.d.) of three independent experiments. C, ChIP experiments analyzed by slot blot show that the level of K9, K14 acetylated histone H3 is increased at the rDNA ARS elements in 3XABF2+ cells. In the graph, the average %IPs (+/− range) are shown for two independent experiments (Pearson coefficient = 0.95). The open triangle above the slot blot represents serial dilutions of input DNA to ensure linearity with respect to hybridization of the probe to the amount of DNA applied to the membrane. Other labels as in Figure 9B.
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pgen-1000047-g009: Cells over-expressing ABF2 have less Sir2p and higher levels of K9, K14 acetylated histone H3 at the rDNA ARS elements.A, Immunoblot showing that the level of Sir2p is not altered in whole cell extracts from cells over-expressing ABF2. The same blot was stained with Ponceau, to indicate loading. Loading was also evaluated from the same samples, with an anti-Cdc28p antibody. B, ChIP experiments analyzed by real-time PCR show that the level of Sir2p (%IP) at the rDNA ARS elements is reduced in 3XABF2+ cells. Part of one rDNA repeat is shown above indicating the location of the rDNA ARS elements, the primers used (primer pairs 20, 21, 22); the nontranscribed spacer (NTS); and the 35S and 5S rRNA genes. The values shown in the bar graph are the average %IPs (±s.d.) of three independent experiments. C, ChIP experiments analyzed by slot blot show that the level of K9, K14 acetylated histone H3 is increased at the rDNA ARS elements in 3XABF2+ cells. In the graph, the average %IPs (+/− range) are shown for two independent experiments (Pearson coefficient = 0.95). The open triangle above the slot blot represents serial dilutions of input DNA to ensure linearity with respect to hybridization of the probe to the amount of DNA applied to the membrane. Other labels as in Figure 9B.

Mentions: The overall levels of Sir2p are not altered in 3xABF2+ cells (Figure 9A). In addition to its roles in silencing, Sir2p negatively affects the activity of origins of DNA replication throughout the genome [16],[17]. Consequently, we next tested if the level of Sir2p at origins of DNA replication is altered in 3xABF2+ cells.


An increase in mitochondrial DNA promotes nuclear DNA replication in yeast.

Blank HM, Li C, Mueller JE, Bogomolnaya LM, Bryk M, Polymenis M - PLoS Genet. (2008)

Cells over-expressing ABF2 have less Sir2p and higher levels of K9, K14 acetylated histone H3 at the rDNA ARS elements.A, Immunoblot showing that the level of Sir2p is not altered in whole cell extracts from cells over-expressing ABF2. The same blot was stained with Ponceau, to indicate loading. Loading was also evaluated from the same samples, with an anti-Cdc28p antibody. B, ChIP experiments analyzed by real-time PCR show that the level of Sir2p (%IP) at the rDNA ARS elements is reduced in 3XABF2+ cells. Part of one rDNA repeat is shown above indicating the location of the rDNA ARS elements, the primers used (primer pairs 20, 21, 22); the nontranscribed spacer (NTS); and the 35S and 5S rRNA genes. The values shown in the bar graph are the average %IPs (±s.d.) of three independent experiments. C, ChIP experiments analyzed by slot blot show that the level of K9, K14 acetylated histone H3 is increased at the rDNA ARS elements in 3XABF2+ cells. In the graph, the average %IPs (+/− range) are shown for two independent experiments (Pearson coefficient = 0.95). The open triangle above the slot blot represents serial dilutions of input DNA to ensure linearity with respect to hybridization of the probe to the amount of DNA applied to the membrane. Other labels as in Figure 9B.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2289842&req=5

pgen-1000047-g009: Cells over-expressing ABF2 have less Sir2p and higher levels of K9, K14 acetylated histone H3 at the rDNA ARS elements.A, Immunoblot showing that the level of Sir2p is not altered in whole cell extracts from cells over-expressing ABF2. The same blot was stained with Ponceau, to indicate loading. Loading was also evaluated from the same samples, with an anti-Cdc28p antibody. B, ChIP experiments analyzed by real-time PCR show that the level of Sir2p (%IP) at the rDNA ARS elements is reduced in 3XABF2+ cells. Part of one rDNA repeat is shown above indicating the location of the rDNA ARS elements, the primers used (primer pairs 20, 21, 22); the nontranscribed spacer (NTS); and the 35S and 5S rRNA genes. The values shown in the bar graph are the average %IPs (±s.d.) of three independent experiments. C, ChIP experiments analyzed by slot blot show that the level of K9, K14 acetylated histone H3 is increased at the rDNA ARS elements in 3XABF2+ cells. In the graph, the average %IPs (+/− range) are shown for two independent experiments (Pearson coefficient = 0.95). The open triangle above the slot blot represents serial dilutions of input DNA to ensure linearity with respect to hybridization of the probe to the amount of DNA applied to the membrane. Other labels as in Figure 9B.
Mentions: The overall levels of Sir2p are not altered in 3xABF2+ cells (Figure 9A). In addition to its roles in silencing, Sir2p negatively affects the activity of origins of DNA replication throughout the genome [16],[17]. Consequently, we next tested if the level of Sir2p at origins of DNA replication is altered in 3xABF2+ cells.

Bottom Line: The Sir2p NAD+-dependent de-acetylase antagonizes this mitochondrial role.We found that cells with increased mitochondrial DNA have reduced Sir2p levels bound at origins of DNA replication in the nucleus, accompanied with increased levels of K9, K14-acetylated histone H3 at those origins.They also suggest that cellular metabolism may impact on chromatin modifications to regulate the activity of origins of DNA replication.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America.

ABSTRACT
Coordination between cellular metabolism and DNA replication determines when cells initiate division. It has been assumed that metabolism only plays a permissive role in cell division. While blocking metabolism arrests cell division, it is not known whether an up-regulation of metabolic reactions accelerates cell cycle transitions. Here, we show that increasing the amount of mitochondrial DNA accelerates overall cell proliferation and promotes nuclear DNA replication, in a nutrient-dependent manner. The Sir2p NAD+-dependent de-acetylase antagonizes this mitochondrial role. We found that cells with increased mitochondrial DNA have reduced Sir2p levels bound at origins of DNA replication in the nucleus, accompanied with increased levels of K9, K14-acetylated histone H3 at those origins. Our results demonstrate an active role of mitochondrial processes in the control of cell division. They also suggest that cellular metabolism may impact on chromatin modifications to regulate the activity of origins of DNA replication.

Show MeSH
Related in: MedlinePlus