Xenopus laevis sperm proteins, previously identified as surface proteins with egg coat binding capability, are indeed histone H4, histone H3, and sperm specific protein SP2

1992 ◽  
Vol 263 (2) ◽  
pp. 210-214 ◽  
Author(s):  
Giovanni Bernardini ◽  
Isabella Dalle Donne ◽  
Sabrina Norreri ◽  
Armando Negri ◽  
Aldo Milzani
Genetics ◽  
2002 ◽  
Vol 162 (2) ◽  
pp. 973-976 ◽  
Author(s):  
Mirela Matecic ◽  
Shelagh Stuart ◽  
Scott G Holmes

Abstract We have identified histone H4 as a high-expression suppressor of Sir2-induced inviability in yeast cells. Overexpression of histone H3 does not suppress Sir2-induced lethality, nor does overexpression of histone H4 alleles associated with silencing defects. These results suggest a direct and specific interaction between Sir2 and H4 in the silencing mechanism.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Wendan Ren ◽  
Huitao Fan ◽  
Sara A. Grimm ◽  
Jae Jin Kim ◽  
Linhui Li ◽  
...  

AbstractDNA methylation and trimethylated histone H4 Lysine 20 (H4K20me3) constitute two important heterochromatin-enriched marks that frequently cooperate in silencing repetitive elements of the mammalian genome. However, it remains elusive how these two chromatin modifications crosstalk. Here, we report that DNA methyltransferase 1 (DNMT1) specifically ‘recognizes’ H4K20me3 via its first bromo-adjacent-homology domain (DNMT1BAH1). Engagement of DNMT1BAH1-H4K20me3 ensures heterochromatin targeting of DNMT1 and DNA methylation at LINE-1 retrotransposons, and cooperates with the previously reported readout of histone H3 tail modifications (i.e., H3K9me3 and H3 ubiquitylation) by the RFTS domain to allosterically regulate DNMT1’s activity. Interplay between RFTS and BAH1 domains of DNMT1 profoundly impacts DNA methylation at both global and focal levels and genomic resistance to radiation-induced damage. Together, our study establishes a direct link between H4K20me3 and DNA methylation, providing a mechanism in which multivalent recognition of repressive histone modifications by DNMT1 ensures appropriate DNA methylation patterning and genomic stability.


2013 ◽  
Vol 33 (16) ◽  
pp. 3286-3298 ◽  
Author(s):  
Zhongqi Ge ◽  
Devi Nair ◽  
Xiaoyan Guan ◽  
Neha Rastogi ◽  
Michael A. Freitas ◽  
...  

The best-characterized acetylation of newly synthesized histone H4 is the diacetylation of the NH2-terminal tail on lysines 5 and 12. Despite its evolutionary conservation, this pattern of modification has not been shown to be essential for either viability or chromatin assembly in any model organism. We demonstrate that mutations in histone H4 lysines 5 and 12 in yeast confer hypersensitivity to replication stress and DNA-damaging agents when combined with mutations in histone H4 lysine 91, which has also been found to be a site of acetylation on soluble histone H4. In addition, these mutations confer a dramatic decrease in cell viability when combined with mutations in histone H3 lysine 56. We also show that mutation of the sites of acetylation on newly synthesized histone H4 results in defects in the reassembly of chromatin structure that accompanies the repair of HO-mediated double-strand breaks. This defect is not due to a decrease in the level of histone H3 lysine 56 acetylation. Intriguingly, mutations that alter the sites of newly synthesized histone H4 acetylation display a marked decrease in levels of phosphorylated H2A (γ-H2AX) in chromatin surrounding the double-strand break. These results indicate that the sites of acetylation on newly synthesized histones H3 and H4 can function in nonoverlapping ways that are required for chromatin assembly, viability, and DNA damage response signaling.


Science ◽  
2021 ◽  
Vol 371 (6527) ◽  
pp. eabc6663
Author(s):  
Marco Igor Valencia-Sánchez ◽  
Pablo De Ioannes ◽  
Miao Wang ◽  
David M. Truong ◽  
Rachel Lee ◽  
...  

Dot1 (disruptor of telomeric silencing-1), the histone H3 lysine 79 (H3K79) methyltransferase, is conserved throughout evolution, and its deregulation is found in human leukemias. Here, we provide evidence that acetylation of histone H4 allosterically stimulates yeast Dot1 in a manner distinct from but coordinating with histone H2B ubiquitination (H2BUb). We further demonstrate that this stimulatory effect is specific to acetylation of lysine 16 (H4K16ac), a modification central to chromatin structure. We provide a mechanism of this histone cross-talk and show that H4K16ac and H2BUb play crucial roles in H3K79 di- and trimethylation in vitro and in vivo. These data reveal mechanisms that control H3K79 methylation and demonstrate how H4K16ac, H3K79me, and H2BUb function together to regulate gene transcription and gene silencing to ensure optimal maintenance and propagation of an epigenetic state.


2020 ◽  
Author(s):  
Shirsendu Ghosh ◽  
Ronen Alon ◽  
Andres Alcover ◽  
Gilad Haran

AbstractWe introduce Microvillar Cartography (MC), a method to map proteins on cellular surfaces with respect to the membrane topography. The surfaces of many cells are not smooth, but are rather covered with various protrusions such as microvilli. These protrusions may play key roles in multiple cellular functions, due to their ability to control the distribution of specific protein assemblies on the cell surface. Thus, for example, we have shown that the T-cell receptor and several of its proximal signaling proteins reside on microvilli, while others are excluded from these projections. These results have indicated that microvilli can function as key signaling hubs for the initiation of the immune response. MC has facilitated our observations of particular surface proteins and their specialized distribution on microvillar and non-microvillar compartments. MC combines membrane topography imaging, using variable-angle total internal microscopy, with stochastic localization nanoscopy, which generates deep sub-diffraction maps of protein distribution. Since the method is based on light microscopy, it avoids some of the pitfalls inherent to electron-microscopy-based techniques, such as dehydration, carbon coating and immunogold clustering, and is amenable to future developments involving e.g. live-cell imaging. This Protocol details the procedures we developed for MC, which can be readily adopted to study a broad range of cell surface molecules and dissect their distribution within distinct surface assemblies under multiple cell activation states.


Development ◽  
1990 ◽  
Vol 110 (2) ◽  
pp. 471-475 ◽  
Author(s):  
D.C. Bennett ◽  
D. Huszar ◽  
P.J. Laipis ◽  
R. Jaenisch ◽  
I.J. Jackson

A mouse cDNA for the developmentally controlled, melanocyte-specific protein, tyrosinase-related protein 1 (TRP-1), was previously cloned and reported to show genetic linkage with the coat-colour locus brown (b) on mouse chromosome 4. The cDNA has been inserted into a retroviral vector derived from Moloney murine leukaemia virus, under the control of the human histone H4 promoter. This vector was used to infect melanocytes of the immortal line melan-b, which are homozygous for the b mutation and which display light brown pigmentation in culture. Infected cultures containing between 0.2 and 2 copies of provirus per cell displayed an altered phenotype: 20–50% of cells now had the black to dark brown colour characteristic of cultured wild-type (Black, B/B) mouse melanocytes. Thus the TRP-1 gene complements the brown mutation. We conclude that TRP-1 is the product of the wild-type b-locus.


2019 ◽  
Vol 47 (14) ◽  
pp. 7392-7401 ◽  
Author(s):  
Kathiresan Selvam ◽  
Sheikh Arafatur Rahman ◽  
Shisheng Li

Abstract Nucleotide excision repair (NER) consists of global genomic NER (GG-NER) and transcription coupled NER (TC-NER) subpathways. In eukaryotic cells, genomic DNA is wrapped around histone octamers (an H3–H4 tetramer and two H2A–H2B dimers) to form nucleosomes, which are well known to profoundly inhibit the access of NER proteins. Through unbiased screening of histone H4 residues in the nucleosomal LRS (loss of ribosomal DNA-silencing) domain, we identified 24 mutations that enhance or decrease UV sensitivity of Saccharomyces cerevisiae cells. The histone H4 H75E mutation, which is largely embedded in the nucleosome and interacts with histone H2B, significantly attenuates GG-NER and Rad26-independent TC-NER but does not affect TC-NER in the presence of Rad26. All the other histone H4 mutations, except for T73F and T73Y that mildly attenuate GG-NER, do not substantially affect GG-NER or TC-NER. The attenuation of GG-NER and Rad26-independent TC-NER by the H4H75E mutation is not due to decreased chromatin accessibility, impaired methylation of histone H3 K79 that is at the center of the LRS domain, or lowered expression of NER proteins. Instead, the attenuation is at least in part due to impaired recruitment of Rad4, the key lesion recognition and verification protein, to chromatin following induction of DNA lesions.


2014 ◽  
Vol 204 (3) ◽  
pp. 313-329 ◽  
Author(s):  
Chin-Chi Chen ◽  
Mekonnen Lemma Dechassa ◽  
Emily Bettini ◽  
Mary B. Ledoux ◽  
Christian Belisario ◽  
...  

Centromeres are specified epigenetically by the incorporation of the histone H3 variant CENP-A. In humans, amphibians, and fungi, CENP-A is deposited at centromeres by the HJURP/Scm3 family of assembly factors, but homologues of these chaperones are absent from a number of major eukaryotic lineages such as insects, fish, nematodes, and plants. In Drosophila, centromeric deposition of CENP-A requires the fly-specific protein CAL1. Here, we show that targeting CAL1 to noncentromeric DNA in Drosophila cells is sufficient to heritably recruit CENP-A, kinetochore proteins, and microtubule attachments. CAL1 selectively interacts with CENP-A and is sufficient to assemble CENP-A nucleosomes that display properties consistent with left-handed octamers. The CENP-A assembly activity of CAL1 resides within an N-terminal domain, whereas the C terminus mediates centromere recognition through an interaction with CENP-C. Collectively, this work identifies the “missing” CENP-A chaperone in flies, revealing fundamental conservation between insect and vertebrate centromere-specification mechanisms.


2006 ◽  
Vol 5 (10) ◽  
pp. 1780-1787 ◽  
Author(s):  
Jeffrey Linger ◽  
Jessica K. Tyler

ABSTRACT The eukaryotic genome is packaged together with histone proteins into chromatin following DNA replication. Recent studies have shown that histones can also be assembled into chromatin independently of DNA replication and that this dynamic exchange of histones may be biased toward sites undergoing transcription. Here we show that epitope-tagged histone H4 can be incorporated into nucleosomes throughout the budding yeast (Saccharomyces cerevisiae) genome regardless of the phase of the cell cycle, the transcriptional status, or silencing of the region. Direct comparisons reveal that the amount of histone incorporation that occurs in G1-arrested cells is similar to that occurring in cells undergoing DNA replication. Additionally, we show that this histone incorporation is not dependent on the histone H3/H4 chaperones CAF-1, Asf1, and Hir1 individually. This study demonstrates that DNA replication and transcription are not necessary prerequisites for histone exchange in budding yeast, indicating that chromatin is more dynamic than previously thought.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 5005-5005
Author(s):  
Jerina Boelens ◽  
Wim Van den Berghe ◽  
Guy Haegeman ◽  
Ann Janssens ◽  
Jan Philippe ◽  
...  

Abstract Aim: The difference in prognosis between B-CLL patients with (M) and wihout (U) somatic hypermutations of the immunoglobulin genes has led to a search for surrogate markers in routine practice. cDNA-Microarray differentiation between M and U led to further analysis of Zap-70, fibromodulin and LPLase, all of which succesfully discriminate the majority of M vs U.. In 1 of 2 proteomic studies searching the difference between M and U B-CLL, nucleophosmin came out as uniformly absent in 6 U patients and present in all 6 with M B-CLL. Nucleophosmin is a nucleolar non-ribosomal protein, associated with cellular proliferation. It is implicated in carcinogenesis as a differentiation blocker in K562 myeloid leukemias where its degradation from a 35 to a 21 kD form accompanies phorbol ester induced differentiation. In K562 this degradation is dependent on P-Erk-translocation to the nucleus that by itself depends on prolonged Erk-activation. We have recently demonstrated that SDF-1, an important microenvironment factor in B-CLL, is capable of inducing prolonged Erk-activation in Zap-70+ but not in Zap-70- B-CLL cells in vitro. This prompted us to study the unstimulated expression of nucleophosmin and other nuclear proteins by Westen blot in 16 patients with B-CLL. Methods: Histones and other alkalic proteins were extracted from the nuclei (pellet fraction) upon treatment with 0.4 M HCl. Following precipitation in acetone, histones and proteins were resuspended in sample buffer and separated by SDS PAGE or acid urea gel electrophoresis. Subsequently, the proteins were electrotransferred to a nitrocellulose membrane. Western blot analysis was performed against nucleophosmin, histone H3 or H4, and final signal detection was revealed by enhanced chemiluminescence reaction. Results: The 35 kD nucleophosmin signal was uniformly expressed in all samples and related to total histone content, irrespective of mutation status, cytogenetics and stage of disease. However, a minor band at 21 kD reflecting degradation was present in 6/6 patients with U B-CLL and absent in 8/10 with M B-CLL. Pan-histone H3 and H4 antibodies revealed similar banding patterns for histone H3 in all patients, but the presence of a heavier (probably ubiquinated) double band for histone H4 in some. This ubiquinated fraction was important in 7/16, faint in 5/16 and absent in 4/16. Morphology was atypical in 4/7 with an important fraction, and typical in all others. 5/7 with important bands and 4/5 with faint bands were M B-CLL against only 1 out of 4 in the group with absence of ubiquitination bands. Discussion: In contrast to previous proteomic studies, we found the 35 kD form of nucleophosmin present in both M and U B-CLL. However, nucleophosmin metabolisation to the 21 kD form is observed preferentially in the U B-CLL. The increased baseline degradation of nucleophosmin in 6/6 U B-CLL all of whom are Zap-70+ can be explained as a downstream nuclear signal from constitutive increased Erk-phosphorylation upon environmental signals in Zap-70+ B-CLL.


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