scholarly journals DNase I hypersensitivity is independent of endogenous topoisomerase II activity during chicken erythrocyte differentiation.

1988 ◽  
Vol 8 (9) ◽  
pp. 3661-3669 ◽  
Author(s):  
M T Muller ◽  
V B Mehta
Keyword(s):  
Topoisomerase Ii ◽  
Globin Gene ◽  
Consensus Sequence ◽  
Dnase I ◽  
Cleavage Sites ◽  
Dnase I Hypersensitivity ◽  
Catalytic Sites ◽  
Hypersensitive Sites ◽  
Single Base Pair

Endogenous topoisomerase II cleavage sites were mapped in the chicken beta A-globin gene of 12- to 14-day embryonic erythrocytes. A major topoisomerase II catalytic site was mapped to the 5' end of the globin gene which contained a nucleosome-free and DNase I-hypersensitive site and additional but minor sites were mapped to the second intron and 3' of the gene to a tissue-specific enhancer. Cleavage sites, mapped in situ by indirect end labeling, were aligned to single-base-pair resolution by comparison to a consensus sequence derived for vertebrate topoisomerase II catalytic sites. In contrast to embryonic erythrocytes, endogenous topoisomerase II cleavages were not detected in erythrocytes from peripheral blood of adult chickens; therefore, as the transcriptional activity of the beta A-globin gene declines during terminal differentiation of erythrocytes, the activity of topoisomerase II in situ declines as well, despite the fact that DNase I hypersensitivity persists. The results showed that DNase I-hypersensitive chromatin can be maintained in the absence of topoisomerase II activity and suggested that topoisomerase II acts at hypersensitive sites because of an inherent attraction to some preexisting combination of DNA sequence or chromatin structure associated with DNase I-hypersensitive regions.

DNase I hypersensitivity is independent of endogenous topoisomerase II activity during chicken erythrocyte differentiation

1988 ◽  
Vol 8 (9) ◽  
pp. 3661-3669
Author(s):  
M T Muller ◽  
V B Mehta
Keyword(s):  
Topoisomerase Ii ◽  
Globin Gene ◽  
Consensus Sequence ◽  
Dnase I ◽  
Cleavage Sites ◽  
Dnase I Hypersensitivity ◽  
Catalytic Sites ◽  
Hypersensitive Sites ◽  
Single Base Pair

Endogenous topoisomerase II cleavage sites were mapped in the chicken beta A-globin gene of 12- to 14-day embryonic erythrocytes. A major topoisomerase II catalytic site was mapped to the 5' end of the globin gene which contained a nucleosome-free and DNase I-hypersensitive site and additional but minor sites were mapped to the second intron and 3' of the gene to a tissue-specific enhancer. Cleavage sites, mapped in situ by indirect end labeling, were aligned to single-base-pair resolution by comparison to a consensus sequence derived for vertebrate topoisomerase II catalytic sites. In contrast to embryonic erythrocytes, endogenous topoisomerase II cleavages were not detected in erythrocytes from peripheral blood of adult chickens; therefore, as the transcriptional activity of the beta A-globin gene declines during terminal differentiation of erythrocytes, the activity of topoisomerase II in situ declines as well, despite the fact that DNase I hypersensitivity persists. The results showed that DNase I-hypersensitive chromatin can be maintained in the absence of topoisomerase II activity and suggested that topoisomerase II acts at hypersensitive sites because of an inherent attraction to some preexisting combination of DNA sequence or chromatin structure associated with DNase I-hypersensitive regions.

Sperm decondensation during fertilisation in the mouse: presence of DNase I hypersensitive sites in situ and a putative role for topoisomerase II

Zygote ◽  
2000 ◽  
Vol 8 (3) ◽  
pp. 197-202 ◽  
Author(s):  
Davide Bizzaro ◽  
Giancarlo Manicardi ◽  
Patrizia Grace Bianchi ◽  
Denny Sakkas
Keyword(s):  
Conformational Changes ◽  
Topoisomerase Ii ◽  
Dnase I ◽  
Dnase I Hypersensitive Sites ◽  
Putative Role ◽  
Hypersensitive Sites ◽  
Dna Alterations ◽  
Sperm Decondensation

In this study our aim was to characterise the presence and the role of DNA alterations during sperm decondensation in the mouse. To visualise the changes during decondensation we investigated for the presence of DNase I hypersensitive sites in situ and for a putative role for topoisomerase II by examining the effect of teniposide, a topoisomerase II inhibitor, during fertilisation. In situ nick translation without the previous addition of DNase I failed to reveal the presence of endogenous nicks in decondensing sperm and pronuclei whereas preincubation of fixed oocytes with DNase I indicated that decondensing sperm were sensitive to this enzyme. Addition of 100 μM teniposide did not completely inhibit pronuclei formation but its addition to the fertilisation medium did lead to the presence of endogenous DNA nicks in decondensing sperm. These observations suggest that DNase I hypersensitivity during sperm decondensation is related to the dramatic conformational changes that the chromatin undergoes during the decondensation process, in which topoisomerase II may be implicated.

scholarly journals Characterization of the DNase I hypersensitive site 3' of the human beta globin gene domain

Blood ◽  
1993 ◽  
Vol 81 (10) ◽  
pp. 2781-2790
Author(s):  
DE Fleenor ◽  
RE Kaufman
Keyword(s):  
Topoisomerase Ii ◽  
Globin Gene ◽  
Dnase I ◽  
Globin Genes ◽  
Beta Globin ◽  
Hypersensitive Site ◽  
Mobility Shift ◽  
Enhancer Activity ◽  
Beta Globin Gene

The members of the human beta globin gene family are flanked by strong DNase I hypersensitive sites. The collection of sites 5' to the epsilon globin gene is able to confer high levels of expression of linked globin genes, but a function has not been assigned to the site 3' to the beta globin gene (3'HS1). Our analysis of this DNase I super hypersensitive site shows that the region is composed of multiple DNase I sites. By examination of the DNA sequence, we have determined that the region is very A/T-rich and contains topoisomerase II recognition sequences, as well as several consensus binding motifs for GATA-1 and AP-1/NF-E2. Gel mobility shift assays indicate that the region can interact in vitro with GATA-1 and AP-1/NF-E2, and functional studies show that the region serves as a scaffold attachment region in both erythroid and nonerythroid cell lines. Whereas many of the physical features of 3'HS1 are shared by 5'HS2 (a component of the 5' locus control region), transient expression studies show that 3' HS1 does not share the erythroid-specific enhancer activity exhibited by 5'HS2.

Correlation between patterns of DNase I-hypersensitive sites and upstream promoter activity of the human epsilon-globin gene at different stages of erythroid development

1990 ◽  
Vol 10 (3) ◽  
pp. 1199-1208
Author(s):  
P Bushel ◽  
K Rego ◽  
L Mendelsohn ◽  
M Allan
Keyword(s):  
Globin Gene ◽  
K562 Cells ◽  
Dnase I ◽  
Base Pairs ◽  
Dnase I Hypersensitive Sites ◽  
Hypersensitive Sites ◽  
Hel Cells ◽  
Globin Synthesis ◽  
Erythroleukemic Cell ◽  
Erythroid Development

DNA 5' to the human epsilon-globin gene exhibits unique patterns of DNase I-hypersensitive sites (DHS) in three human erythroleukemic cell lines which represent the embryonic (K562), fetal (HEL), and adult (KMOE) stages of erythroid development. We have mapped 10 epsilon-globin DHS in K562 cells, in which the epsilon-globin gene is maximally active. Major sites are located -11.7, -10.5, -6.5, -2.2 kilobase pairs (kbp) and -200 base pairs (bp) upstream of the gene and directly over the major cap site. Minor sites are located -5.5, -4.5, and -1.48 kbp and -900 bp upstream of the cap site. In HEL cells, in which the epsilon-globin gene is expressed at extremely low levels, the -11.7-, -10.5-, -5.5-, -4.5-, and -2.2-kbp DHS are no longer detectable; the -200-bp site is approximately 300-fold less sensitive to DNase I; and the -1.48-kbp, -900-bp, and major cap site DHS are 3- to 4-fold less sensitive. Only the DHS located -6.5 kbp relative to the major cap site is detectable at all three stages of erythroid development, including KMOE cells in which epsilon-globin synthesis is undetectable. We suggest that this site may be implicated in maintaining the entire beta-globin cluster in an active chromatin conformation. The five DHS downstream of the -6.5-kbp element possess associated promoters. Thus two distinct types of DHS exist--promoter positive and promoter negative. In HEL cells, all the upstream promoters are inactivated, although the -1.48-kbp and -900- and -200-bp DHS are still present. This suggests that the maintenance of DHS and regulation of their associated promoters occur by independent mechanisms. The inactivation of the upstream promoters in HEL cells while the major cap site remains active represents a unique pattern of expression and suggests that HEL cells possess regulatory factors which specifically down regulate the epsilon-globin upstream promoters.

scholarly journals The Ly-6E.1 (Sca-1) gene requires a 3' chromatin-dependent region for high-level gamma-interferon-induced hematopoietic cell expression

Blood ◽  
1996 ◽  
Vol 87 (7) ◽  
pp. 2750-2761 ◽  
Author(s):  
A Sinclair ◽  
B Daly ◽  
E Dzierzak
Keyword(s):  
Consensus Sequence ◽  
Hematopoietic Cells ◽  
Regulatory Elements ◽  
Dnase I ◽  
Gamma Interferon ◽  
Hematopoietic Cell ◽  
Hematopoietic Stem ◽  
Dnase I Hypersensitive Sites ◽  
Hypersensitive Sites ◽  
High Level

The Ly-6E.1/A.2 gene product recognized by the Sca-1 antibody has been found on murine hematopoietic stem cells and some hematopoietic precursors, T lymphocytes, and nonhematopoietic cell lineages, suggesting a complex array of gene regulatory elements. The ability to use the Ly6E.1/A.2 transcriptional regulatory elements to direct expression of heterologous genes will allow for the manipulation of these cells during development and in hematopoietic cell transplantations. To identify the elements necessary for high-level expression, we have made deletion constructs of Ly-6E.1 gene flanking regions containing DNase I hypersensitive sites, tested them for expression in hematopoietic cells, and have performed kinetic analyses to correlate the appearance of hypersensitive sites with gene transcription and protein expression. We show that a 3′ region containing two DNase I hypersensitive sites at +8.7 and +8.9 kb is required for high-level, gamma-interferon (gamma-IFN)-induced expression of the Ly-6E.1 gene and that a consensus sequence for a gamma-IFN-responsive element localizes to the +8.7 site. We also provide a description of allele- and cell-specific DNase I hypersensitive site patterns of the Ly-6E.1 and Ly-6A.2 genes. Taken together, these data indicate that while both 5′ and 3′ hypersensitive sites are rapidly induced with gamma-IFN, the 3′ most distal hypersensitive sites are involved in directing high levels of expression of Sca-1 in hematopoietic cells.

scholarly journals Synergistic and Additive Properties of the Beta-Globin Locus Control Region (LCR) Revealed by 5′HS3 Deletion Mutations: Implication for LCR Chromatin Architecture

2005 ◽  
Vol 25 (16) ◽  
pp. 7033-7041 ◽  
Author(s):  
Xiangdong Fang ◽  
Jin Sun ◽  
Ping Xiang ◽  
Man Yu ◽  
Patrick A. Navas ◽  
...  
Keyword(s):  
Histone Acetylation ◽  
Control Region ◽  
Chromatin Structure ◽  
Globin Gene ◽  
Dnase I ◽  
Beta Globin ◽  
Pol Ii ◽  
Dnase I Hypersensitive Sites ◽  
Chromatin Architecture ◽  
Hypersensitive Sites

ABSTRACT Deletion of the 234-bp core element of the DNase I hypersensitive site 3 (5′HS3) of the locus control region (LCR) in the context of a human beta-globin locus yeast artificial chromosome (β-YAC) results in profound effects on globin gene expression in transgenic mice. In contrast, deletion of a 2.3-kb 5′HS3 region, which includes the 234-bp core sequence, has a much milder phenotype. Here we report the effects of these deletions on chromatin structure in the beta-globin locus of adult erythroblasts. The 234-bp 5′HS3 deletion abolished histone acetylation throughout the β-globin locus; recruitment of RNA polymerase II (pol II) to the LCR and beta-globin gene promoter was reduced to a basal level; and formation of all the 5′ DNase I hypersensitive sites of the LCR was disrupted. The 2.3-kb 5′HS3 deletion mildly reduced the level of histone acetylation but did not change the profile across the whole locus; the 5′ DNase I hypersensitive sites of the LCR were formed, but to a lesser extent; and recruitment of pol II was reduced, but only marginally. These data support the hypothesis that the LCR forms a specific chromatin structure and acts as a single entity. Based on these results we elaborate on a model of LCR chromatin architecture which accommodates the distinct phenotypes of the 5′HS3 and HS3 core deletions.

Localization of DNase I hypersensitive sites in the human oestrogen receptor gene correlates with the transcriptional activity of two differentially used promoters

1993 ◽  
Vol 10 (3) ◽  
pp. 269-277 ◽  
Author(s):  
K F H Grandien ◽  
A Berkenstam ◽  
S Nilsson ◽  
J-Å Gustafsson
Keyword(s):  
Cell Line ◽  
Cell Lines ◽  
Oestrogen Receptor ◽  
Transcriptional Activity ◽  
Receptor Gene ◽  
Dnase I ◽  
Dnase I Hypersensitivity ◽  
Hypersensitive Sites ◽  
Promoter Usage ◽  
Mcf 7

ABSTRACT The human oestrogen receptor (hER) gene has recently been shown to be transcribed from two different promoters. In order to study the hER gene promoter region we initially isolated and sequenced 3·3 kb of the 5′ region of the hER gene. DNase I hypersensitivity experiments with nuclei from the ER-expressing cell line MCF-7 mapped three different hypersensitive sites, located in the vicinity of the two hER promoters previously identified. However, in another ER-positive cell line, ZR-75-1, DNase I hypersensitivity was observed only in the region of the downstream promoter, suggesting differences between the two cell lines in promoter usage. Polymerase chain reaction-mediated detection of mRNAs transcribed from the two different promoters demonstrated transcripts from the downstream promoter in both the cell lines studied. However, mRNAs transcribed from the upstream promoter could only be detected in MCF-7 cells. Thus, the pattern of DNase I hypersensitivity correlates with the transcriptional activity of the two promoters in the hER gene. Based on these data, we suggest that differential promoter usage might be a novel level of regulation of the hER gene.

Sign in / Sign up

Export Citation Format

Share Document