scholarly journals Asynchronous appearance of newly synthesized histone H1 subfractions in HeLa chromatin.

1981 ◽  
Vol 90 (2) ◽  
pp. 415-417 ◽  
Author(s):  
S R Sizemore ◽  
R D Cole
Keyword(s):  
Hela Cells ◽  
Histone H1 ◽  
S Phase ◽  
H1 Histone ◽  
Chromatographic Peaks

Incorporation of radioactive alanine into chromatin-bound subfractions of H1 histone was studied in HeLa cells synchronized by the double thymidine block technique. The subfractions were resolved into three chromatographic peaks by Biorex-70. In the period 5-7 h after release from the thymidine block, peaks I and III showed twice as much incorporation as they did in the period 1-3 h after release, whereas peak II showed three times the incorporation at 5-7 h that it did at 1-3 h. Thus, the H1-histone subfraction in peak II appears in chromatin somewhat later in S phase than do the subfractions in Peaks I and III.

scholarly journals Dynamic behavior of histone H1 microinjected into HeLa cells.

1986 ◽  
Vol 103 (2) ◽  
pp. 465-474 ◽  
Author(s):  
L H Wu ◽  
L Kuehl ◽  
M Rechsteiner
Keyword(s):  
Hela Cells ◽  
High Mobility ◽  
Histone H1 ◽  
S Phase ◽  
Reductive Methylation ◽  
High Mobility Group Proteins ◽  
3T3 Fibroblasts ◽  
Human Genomes ◽  
Chloramine T ◽  
Human And Mouse

Histone H1 was purified from bovine thymus and radiolabeled with tritium by reductive methylation or with 125I using chloramine-T. Red blood cell-mediated microinjection was then used to introduce the labeled H1 molecules into HeLa cells synchronized in S phase. The injected H1 molecules rapidly entered HeLa nuclei, and a number of tests indicate that their association with chromatin was equivalent to that endogenous histone H1. The injected molecules copurified with HeLa cell nucleosomes, exhibited a half-life of approximately 100 h, and were hyperphosphorylated at mitosis. When injected HeLa cells were fused with mouse 3T3 fibroblasts less than 10% of the labeled H1 molecules migrated to mouse nuclei during the next 48 h. Thus, the intracellular behavior of histone H1 differs markedly from that of high mobility group proteins 1 and 2 (HMG1 and HMG2), which rapidly equilibrate between human and mouse nuclei after heterokaryon formation (Rechsteiner, M., and L. Kuehl, 1979, Cell, 16:901-908; Wu, L., M. Rechsteiner, and L. Kuehl, 1981, J. Cell Biol, 91: 488-496). Despite their slow rate of migration between nuclei, the injected H1 molecules were evenly distributed on mouse and human genomes soon after mitosis of HeLa-3T3 heterokaryons. These results suggest that although most histone H1 molecules are stably associated with interphase chromatin, they undergo extensive redistribution after mitosis.

ATF is important to late S phase-dependent regulation of DNA topoisomerase IIα gene expression in HeLa cells

2002 ◽  
Vol 184 (1) ◽  
pp. 81-88 ◽  
Author(s):  
Mee-Young Son ◽  
Tae-Jeong Kim ◽  
Kwang-In Kweon ◽  
Jong-Il Park ◽  
Chung Park ◽  
...  
Keyword(s):  
Gene Expression ◽  
Hela Cells ◽  
S Phase ◽  
Topoisomerase Iiα ◽  
Dna Topoisomerase ◽  
Dna Topoisomerase Iiα

scholarly journals Histone H1 Is Dispensable for Methylation-Associated Gene Silencing in Ascobolus immersusand Essential for Long Life Span

2000 ◽  
Vol 20 (1) ◽  
pp. 61-69 ◽  
Author(s):  
Jose L. Barra ◽  
Laïla Rhounim ◽  
Jean-Luc Rossignol ◽  
Godeleine Faugeron
Keyword(s):  
Gene Silencing ◽  
Life Span ◽  
Sequence Similarity ◽  
Histone H1 ◽  
Peptide Sequence ◽  
Micrococcal Nuclease ◽  
Gene Encoding ◽  
H1 Histone ◽  
Mutant Strains ◽  
Long Life

ABSTRACT A gene encoding a protein that shows sequence similarity with the histone H1 family only was cloned in Ascobolus immersus. The deduced peptide sequence presents the characteristic three-domain structure of metazoan linker histones, with a central globular region, an N-terminal tail, and a long positively charged C-terminal tail. By constructing an artificial duplication of this gene, namedH1, it was possible to methylate and silence it by the MIP (methylation induced premeiotically) process. This resulted in the complete loss of the Ascobolus H1 histone. Mutant strains lacking H1 displayed normal methylation-associated gene silencing, underwent MIP, and showed the same methylation-associated chromatin modifications as did wild-type strains. However, they displayed an increased accessibility of micrococcal nuclease to chromatin, whether DNA was methylated or not, and exhibited a hypermethylation of the methylated genome compartment. These features are taken to imply thatAscobolus H1 histone is a ubiquitous component of chromatin which plays no role in methylation-associated gene silencing. Mutant strains lacking histone H1 reproduced normally through sexual crosses and displayed normal early vegetative growth. However, between 6 and 13 days after germination, they abruptly and consistently stopped growing, indicating that Ascobolus H1 histone is necessary for long life span. This constitutes the first observation of a physiologically important phenotype associated with the loss of H1.

scholarly journals Histone H1 interphase phosphorylation becomes largely established in G1 or early S phase and differs in G1 between T-lymphoblastoid cells and normal T cells

2011 ◽  
Vol 4 (1) ◽  
pp. 15 ◽  
Author(s):  
Anna Gréen ◽  
Bettina Sarg ◽  
Henrik Gréen ◽  
Anita Lönn ◽  
Herbert H Lindner ◽  
...  
Keyword(s):  
T Cells ◽  
Histone H1 ◽  
S Phase ◽  
Lymphoblastoid Cells

scholarly journals Lamin-binding Fragment of LAP2 Inhibits Increase in Nuclear Volume during the Cell Cycle and Progression into S Phase

1997 ◽  
Vol 139 (5) ◽  
pp. 1077-1087 ◽  
Author(s):  
Li Yang ◽  
Tinglu Guan ◽  
Larry Gerace
Keyword(s):  
Cell Cycle ◽  
Hela Cells ◽  
Nuclear Lamina ◽  
Normal Function ◽  
S Phase ◽  
Nuclear Volume ◽  
G1 Phase ◽  
Binding Region ◽  
Recombinant Polypeptide ◽  
Volume Increase

Lamina-associated polypeptide 2 (LAP2) is an integral membrane protein of the inner nuclear membrane that binds to both lamin B and chromatin and has a putative role in nuclear envelope (NE) organization. We found that microinjection of a recombinant polypeptide comprising the nucleoplasmic domain of rat LAP2 (residues 1–398) into metaphase HeLa cells does not affect the reassembly of transport-competent nuclei containing NEs and lamina, but strongly inhibits nuclear volume increase. This effect appears to be specifically due to lamin binding, because it also is caused by microinjection of the minimal lamin-binding region of LAP2 (residues 298–373) but not by the chromatin-binding domain (residues 1–88). Injection of the lamin-binding region of rat LAP2 into early G1 phase HeLa cells also strongly affects nuclear growth; it almost completely prevents the threefold nuclear volume increase that normally occurs during the ensuing 10 h. Moreover, injection of the fragment during early G1 phase strongly inhibits entry of cells into S phase, whereas injection during S phase has no apparent effect on ongoing DNA replication. Since the lamin-binding fragment of LAP2 most likely acts by inhibiting dynamics of the nuclear lamina, our results suggest that a normal function of LAP2 involves regulation of nuclear lamina growth. These data also suggest that lamina dynamics are required for growth of the NE and for nuclear volume increase during the cell cycle, and that progression into S phase is dependent on the acquisition of a certain nuclear volume.

scholarly journals Fluctuation in radioresponse of HeLa cells during the cell cycle evaluated based on micronucleus frequency

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hiroaki Shimono ◽  
Atsushi Kaida ◽  
Hisao Homma ◽  
Hitomi Nojima ◽  
Yusuke Onozato ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Hela Cells ◽  
Time Lapse ◽  
S Phase ◽  
G1 Phase ◽  
M Phase ◽  
G2 Phase ◽  
The Difference ◽  
Time Lapse Imaging ◽  
First Time

AbstractIn this study, we examined the fluctuation in radioresponse of HeLa cells during the cell cycle. For this purpose, we used HeLa cells expressing two types of fluorescent ubiquitination-based cell cycle indicators (Fucci), HeLa-Fucci (CA)2 and HeLa-Fucci (SA), and combined this approach with the micronucleus (MN) assay to assess radioresponse. The Fucci system distinguishes cell cycle phases based on the colour of fluorescence and cell morphology under live conditions. Time-lapse imaging allowed us to further identify sub-positions within the G1 and S phases at the time of irradiation by two independent means, and to quantitate the number of MNs by following each cell through M phase until the next G1 phase. Notably, we found that radioresponse was low in late G1 phase, but rapidly increased in early S phase. It then decreased until late S phase and increased in G2 phase. For the first time, we demonstrated the unique fluctuation of radioresponse by the MN assay during the cell cycle in HeLa cells. We discuss the difference between previous clonogenic experiments using M phase-synchronised cell populations and ours, as well as the clinical implications of the present findings.

Comparative Enzymatic Degradation of H1 Subfractions from Syrian Hamster Tissues

1986 ◽  
Vol 41 (7-8) ◽  
pp. 776-780
Author(s):  
Elżbieta Hrabec ◽  
Anna Płucienniczak ◽  
Henryk Panusz
Keyword(s):  
Electrophoretic Mobility ◽  
Syrian Hamster ◽  
Cleavage Site ◽  
Enzymatic Degradation ◽  
Histone H1 ◽  
Polyacrylamide Gels ◽  
H1 Histone ◽  
Bothrops Marajoensis ◽  
Bothrops Moojeni

Abstract An additional hydrolysis site recognized by thrombin on histone H1 molecules was found. Snakes venom proteases from Agkistrodon rhodostoma, Bothrops marajoensis and Bothrops moojeni were further used for the analysis of H1 histones. The presence of the main cleavage site on H1 histone molecules has been established. This site is localized on main N-terminal thrombin peptide. The main venom protease peptides obtained from different H1 subfractions preserve differences of electrophoretic mobility in acid-urea polyacrylamide gels typical for the initial H1 subfractions.

scholarly journals In vivo and in vitro analysis of transcriptional activation mediated by the human cytomegalovirus major immediate-early proteins.

1993 ◽  
Vol 13 (2) ◽  
pp. 1238-1250 ◽  
Author(s):  
K M Klucher ◽  
M Sommer ◽  
J T Kadonaga ◽  
D H Spector
Keyword(s):  
Human Cytomegalovirus ◽  
Hela Cells ◽  
Transcriptional Activation ◽  
Histone H1 ◽  
Early Gene ◽  
Immediate Early ◽  
Early Promoter ◽  
Drosophila Embryos

To define mechanistically how the human cytomegalovirus (HCMV) major immediate-early (IE) proteins induce early-gene transcription, the IE1 72-kDa protein, the IE2 55-kDa protein, and the IE2 86-kDa protein were analyzed for their ability to activate transcription from an HCMV early promoter in vivo and in vitro. In transient-expression assays in U373MG astrocytoma/glioblastoma and HeLa cells, only the IE2 86-kDa protein was able to activate the HCMV early promoter to high levels. In HeLa cells, the IE1 72-kDa protein was able to activate the promoter to a low but detectable level, and the level of promoter activity observed in response to the IE2 86-kDa protein was increased synergistically following cotransfection of the constructs expressing both IE proteins. To examine the interaction of the HCMV IE proteins with the RNA polymerase II transcription machinery, we assayed the ability of Escherichia coli-synthesized proteins to activate the HCMV early promoter in nuclear extracts prepared from U373MG cells, HeLa cells, and Drosophila embryos. The results of the in vitro experiments correlated well with those obtained in vivo. The basal activity of the promoter was minimal in both the HeLa and U373MG extracts but was stimulated 6- to 10-fold by the IE2 86-kDa protein. With a histone H1-deficient extract from Drosophila embryos, the HCMV early promoter was quite active and was stimulated two- to fourfold by the IE2 86-kDa protein. Addition of histone H1 at 1 molecule per 40 to 50 bp of DNA template significantly repressed basal transcription from this promoter. However, the IE2 86-kDa protein, but none of the other IE proteins, was able to counteract the H1-mediated repression and stimulate transcription at least 10- to 20-fold. The promoter specificity of the activation was demonstrated by the inability of the IE2 86-kDa protein to activate the Drosophila Krüppel promoter in either the presence or absence of histone H1. These results suggest that one mechanism of transcription activation by the IE2 86-kDa protein involves antirepression.

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