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Histone acetyl transferase 1 is essential for mammalian development, genome stability, and the processing of newly synthesized histones H3 and H4.

Nagarajan P, Ge Z, Sirbu B, Doughty C, Agudelo Garcia PA, Schlederer M, Annunziato AT, Cortez D, Kenner L, Parthun MR - PLoS Genet. (2013)

Bottom Line: Murine Hat1 is essential for viability, as homozygous deletion of Hat1 results in neonatal lethality.The neonatal lethality is due to severe defects in lung development that result in less aeration and respiratory distress.Many of the Hat1(-/-) neonates also display significant craniofacial defects with abnormalities in the bones of the skull and jaw.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, OH, USA.

ABSTRACT
Histone acetyltransferase 1 is an evolutionarily conserved type B histone acetyltransferase that is thought to be responsible for the diacetylation of newly synthesized histone H4 on lysines 5 and 12 during chromatin assembly. To understand the function of this enzyme in a complex organism, we have constructed a conditional mouse knockout model of Hat1. Murine Hat1 is essential for viability, as homozygous deletion of Hat1 results in neonatal lethality. The lungs of embryos and pups genetically deficient in Hat1 were much less mature upon histological evaluation. The neonatal lethality is due to severe defects in lung development that result in less aeration and respiratory distress. Many of the Hat1(-/-) neonates also display significant craniofacial defects with abnormalities in the bones of the skull and jaw. Hat1(-/-) mouse embryonic fibroblasts (MEFs) are defective in cell proliferation and are sensitive to DNA damaging agents. In addition, the Hat1(-/-) MEFs display a marked increase in genome instability. Analysis of histone dynamics at sites of replication-coupled chromatin assembly demonstrates that Hat1 is not only responsible for the acetylation of newly synthesized histone H4 but is also required to maintain the acetylation of histone H3 on lysines 9, 18, and 27 during replication-coupled chromatin assembly.

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Related in: MedlinePlus

Hat1 is essential for the acetylation of newly synthesized histones.Hat1+/+ and Hat1−/− MEFs were pulse-labeled with 3H-lysine for 12 minutes. Histones were then isolated and resolved by Acid-Urea (AU) gel electrophoresis. Total protein was visualized with Coomassie blue staining and radio-labeled proteins visualized by fluorography (as indicated). The mobility of each histone is indicated. The brackets indicate the regions of mobility for the acetylated isoforms of histone H4 and histone H3.
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pgen-1003518-g007: Hat1 is essential for the acetylation of newly synthesized histones.Hat1+/+ and Hat1−/− MEFs were pulse-labeled with 3H-lysine for 12 minutes. Histones were then isolated and resolved by Acid-Urea (AU) gel electrophoresis. Total protein was visualized with Coomassie blue staining and radio-labeled proteins visualized by fluorography (as indicated). The mobility of each histone is indicated. The brackets indicate the regions of mobility for the acetylated isoforms of histone H4 and histone H3.

Mentions: The effect of Hat1 on the acetylation state of histones incorporated during replication-coupled chromatin assembly suggested that Hat1 is modifying newly synthesized molecules. To test this, Hat1+/+ and Hat1−/− MEFs were briefly pulsed with 3H-lysine to radiolabel newly synthesized proteins. Histones were then purified from these cells by acid extraction and resolved by acid-urea (AU) gel electrophoresis. AU gels are capable of resolving the acetylated isoforms of histones where the addition of each acetyl groups causes a successive decrease in electrophoretic mobility. The AU gels were stained with coomassie blue and then processed for fluorography (Figure 7). The coomassie blue stained gel shows the mobility and distribution of bulk histones. The absence of Hat1 had little effect on the bulk histones. Examining the radiolabeled histones provides specific information on the distribution of acetylated isoforms of the newly synthesized histones. In Hat1 WT cells, essentially all of the newly synthesized histone H4 migrated at a position consistent with the diacetylated state, in agreement with previous reports. However, in the absence of Hat1, it appeared that nearly all of the newly synthesized histone H4 was found to be unacetylated. This conclusively demonstrates that Hat1 is involved in the acetylation of newly synthesized histone H4 and appears to be the only enzyme responsible for this pattern of acetylation.


Histone acetyl transferase 1 is essential for mammalian development, genome stability, and the processing of newly synthesized histones H3 and H4.

Nagarajan P, Ge Z, Sirbu B, Doughty C, Agudelo Garcia PA, Schlederer M, Annunziato AT, Cortez D, Kenner L, Parthun MR - PLoS Genet. (2013)

Hat1 is essential for the acetylation of newly synthesized histones.Hat1+/+ and Hat1−/− MEFs were pulse-labeled with 3H-lysine for 12 minutes. Histones were then isolated and resolved by Acid-Urea (AU) gel electrophoresis. Total protein was visualized with Coomassie blue staining and radio-labeled proteins visualized by fluorography (as indicated). The mobility of each histone is indicated. The brackets indicate the regions of mobility for the acetylated isoforms of histone H4 and histone H3.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3675013&req=5

pgen-1003518-g007: Hat1 is essential for the acetylation of newly synthesized histones.Hat1+/+ and Hat1−/− MEFs were pulse-labeled with 3H-lysine for 12 minutes. Histones were then isolated and resolved by Acid-Urea (AU) gel electrophoresis. Total protein was visualized with Coomassie blue staining and radio-labeled proteins visualized by fluorography (as indicated). The mobility of each histone is indicated. The brackets indicate the regions of mobility for the acetylated isoforms of histone H4 and histone H3.
Mentions: The effect of Hat1 on the acetylation state of histones incorporated during replication-coupled chromatin assembly suggested that Hat1 is modifying newly synthesized molecules. To test this, Hat1+/+ and Hat1−/− MEFs were briefly pulsed with 3H-lysine to radiolabel newly synthesized proteins. Histones were then purified from these cells by acid extraction and resolved by acid-urea (AU) gel electrophoresis. AU gels are capable of resolving the acetylated isoforms of histones where the addition of each acetyl groups causes a successive decrease in electrophoretic mobility. The AU gels were stained with coomassie blue and then processed for fluorography (Figure 7). The coomassie blue stained gel shows the mobility and distribution of bulk histones. The absence of Hat1 had little effect on the bulk histones. Examining the radiolabeled histones provides specific information on the distribution of acetylated isoforms of the newly synthesized histones. In Hat1 WT cells, essentially all of the newly synthesized histone H4 migrated at a position consistent with the diacetylated state, in agreement with previous reports. However, in the absence of Hat1, it appeared that nearly all of the newly synthesized histone H4 was found to be unacetylated. This conclusively demonstrates that Hat1 is involved in the acetylation of newly synthesized histone H4 and appears to be the only enzyme responsible for this pattern of acetylation.

Bottom Line: Murine Hat1 is essential for viability, as homozygous deletion of Hat1 results in neonatal lethality.The neonatal lethality is due to severe defects in lung development that result in less aeration and respiratory distress.Many of the Hat1(-/-) neonates also display significant craniofacial defects with abnormalities in the bones of the skull and jaw.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, OH, USA.

ABSTRACT
Histone acetyltransferase 1 is an evolutionarily conserved type B histone acetyltransferase that is thought to be responsible for the diacetylation of newly synthesized histone H4 on lysines 5 and 12 during chromatin assembly. To understand the function of this enzyme in a complex organism, we have constructed a conditional mouse knockout model of Hat1. Murine Hat1 is essential for viability, as homozygous deletion of Hat1 results in neonatal lethality. The lungs of embryos and pups genetically deficient in Hat1 were much less mature upon histological evaluation. The neonatal lethality is due to severe defects in lung development that result in less aeration and respiratory distress. Many of the Hat1(-/-) neonates also display significant craniofacial defects with abnormalities in the bones of the skull and jaw. Hat1(-/-) mouse embryonic fibroblasts (MEFs) are defective in cell proliferation and are sensitive to DNA damaging agents. In addition, the Hat1(-/-) MEFs display a marked increase in genome instability. Analysis of histone dynamics at sites of replication-coupled chromatin assembly demonstrates that Hat1 is not only responsible for the acetylation of newly synthesized histone H4 but is also required to maintain the acetylation of histone H3 on lysines 9, 18, and 27 during replication-coupled chromatin assembly.

Show MeSH
Related in: MedlinePlus