scholarly journals Possible role of histone acetylation and histone H1° replacement for the initiation of replication in regenerating rat liver

1991 ◽  
Vol 280 (3) ◽  
pp. 777-781
Author(s):  
G Weiss ◽  
H Talasz ◽  
B Puschendorf
Keyword(s):  
Dna Synthesis ◽  
Histone Acetylation ◽  
Rat Liver ◽  
Histone Acetyltransferase ◽  
Histone H1 ◽  
Acetyltransferase Activity ◽  
Initiation Of Replication ◽  
Histone Acetyltransferase Activity

The role of histone acetylation and DNA synthesis has been investigated extensively in the regenerating rat liver system in the presence and absence of the cyclophosphamide derivative mafosfamide. We demonstrate a mafosfamide-induced inhibition of maximum histone acetyltransferase activity followed by a second elevation of enzyme activity and an accompanying total suppression of DNA synthesis for 7-8 h. The maximum of histone acetyltransferase activity, in parallel with an elevated acetylation in vivo, the consecutive replacement of histone H1(0) amd initiation of replication occur sequentially in the presence and absence of mafosfamide, but with a temporary delay of 7-8 h. Our data indicate that modifications of histone acetyltransferase (EC 2.3.1.48) activity do not significantly influence the acetylation patterns of histones H3 and H4. The mafosfamide-induced change of histone acetyltransferase activity and acetylation in vivo, the shift of histone H1(0) exchange and the consecutive transition of initiation of replication suggest that these three events might be functionally related.

scholarly journals Modulation of Histone Acetyltransferase Activity through Interaction of Epstein-Barr Nuclear Antigen 3C with Prothymosin Alpha

2000 ◽  
Vol 20 (15) ◽  
pp. 5722-5735 ◽  
Author(s):  
Murray A. Cotter ◽  
Erle S. Robertson
Keyword(s):  
Histone Acetylation ◽  
B Lymphocytes ◽  
Histone Acetyltransferase ◽  
Critical Role ◽  
Cellular Protein ◽  
Nuclear Antigen ◽  
Acetyltransferase Activity ◽  
Prothymosin Alpha ◽  
Epstein Barr ◽  
Histone Acetyltransferase Activity

ABSTRACT The Epstein-Barr virus (EBV) nuclear antigen 3C (EBNA3C) is essential for EBV-dependent immortalization of human primary B lymphocytes. Genetic analysis indicated that amino acids 365 to 992 are important for EBV-mediated immortalization of B lymphocytes. We demonstrate that this region of EBNA3C critical for immortalization interacts with prothymosin alpha (ProTα), a cellular protein previously identified to be important for cell division and proliferation. This interaction maps to a region downstream of amino acid 365 known to be involved in transcription regulation and critical for EBV-mediated transformation of primary B lymphocytes. Additionally, we show that EBNA3C also interacts with p300, a cellular acetyltransferase. This interaction suggests a possible role in regulation of histone acetylation and chromatin remodeling. An increase in histone acetylation was observed in EBV-transformed lymphoblastoid cell lines, which is consistent with increased cellular gene expression. These cells express the entire repertoire of latent nuclear antigens, including EBNA3C. Expression of EBNA3C in cells with increased acetyltransferase activity mediated by the EBV transactivator EBNA2 results in down-modulation of this activity in a dose-responsive manner. The interactions of EBNA3C with ProTα and p300 provide new evidence implicating this essential EBV protein EBNA3C in modulating the acetylation of cellular factors, including histones. Hence, EBNA3C plays a critical role in balancing cellular transcriptional events by linking the biological property of mediating inhibition of EBNA2 transcription activation and the observed histone acetyltransferase activity, thereby orchestrating immortalization of EBV-infected cells.

Partial Characterization of a Histone Acetyltransferase from Trout Testis

1975 ◽  
Vol 53 (7) ◽  
pp. 796-803 ◽  
Author(s):  
E. P. M. Candido
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Histone Acetyltransferase ◽  
Ph Optimum ◽  
Acetyltransferase Activity ◽  
Nuclear Extracts ◽  
Specific Activities ◽  
Histone Acetyltransferase Activity

Histone acetyltransferase activity of trout testis was studied both in intact nuclei, and in high salt nuclear extracts, With intact nuclei, the distribution of incorporated [14C]acetate in the various histones was similar to that observed in vivo; the arginine-rich histones H3 and H4 showed the highest specific activities, and lower amounts of label were detected in histones H2a and H2b. Histone H1 incorporated little or no label. Acetyltransferase activity could be detected in purified, sheared chromatin after the addition of MgCl2 or KCl, suggesting that the enzyme is bound to chromatin.Treatment of nuclei with 0,4 M NaCl caused the dissociation of acetyltransferase activity. Most of this solubilized activity failed to bind to DEAE Sephadex and behaved as a high molecular weight heterogeneous complex on Sephadex G-100, suggesting that the enzyme is present as an aggregate with other proteins in the extract. The pH optimum of this preparation was approximately 8.5, and the enzyme showed a preference for histones H3 and H4 as substrates.

scholarly journals Histone acetyltransferase activity of yeast Gcn5p is required for the activation of target genes in vivo

1998 ◽  
Vol 12 (5) ◽  
pp. 627-639 ◽  
Author(s):  
M.-H. Kuo ◽  
J. Zhou ◽  
P. Jambeck ◽  
M. E.A. Churchill ◽  
C. D. Allis
Keyword(s):  
Target Genes ◽  
Histone Acetyltransferase ◽  
Acetyltransferase Activity ◽  
Histone Acetyltransferase Activity

scholarly journals A single histone acetyltransferase from Tetrahymena macronuclei catalyzes deposition-related acetylation of free histones and transcription-related acetylation of nucleosomal histones.

1987 ◽  
Vol 105 (1) ◽  
pp. 127-135 ◽  
Author(s):  
L G Chicoine ◽  
R Richman ◽  
R G Cook ◽  
M A Gorovsky ◽  
C D Allis
Keyword(s):  
Enzyme Activity ◽  
Histone Acetylation ◽  
Histone Acetyltransferase ◽  
Histone H3 ◽  
Heat Inactivation ◽  
Histone H4 ◽  
Isolated Nuclei ◽  
Core Histones ◽  
Histone Acetyltransferase Activity

A salt-extracted histone acetyltransferase activity from Tetrahymena macronuclei acetylates mostly histone H3 and H4 when free histones are used as substrate. Free histone H4 is acetylated first at position 11 (monoacetylated) or positions 11 and 4 (diacetylated). This activity strongly resembles in vivo, deposition-related acetylation of newly synthesized histones. When acetylase-free mononucleosomes are used as substrate, all four core histones are acetylated by the same extract, and H4 is acetylated first at position 7 (monoacetylated) or positions 7 and 4 (diacetylated). In this respect, the activity of the extract is indistinguishable from postsynthetic, transcription-related histone acetylation that occurs in vivo or in isolated nuclei. Heat inactivation curves with both substrates are indistinguishable, and free histones compete with chromatin for limiting amounts of enzyme activity. These results argue strongly that two distinct, biologically important histone acetylations, one deposition related and one transcription related, are carried out by a single acetyltransferase.

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