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Notes on Genetic and Radiation Control of Senescence
Published in Nate F. Cardarelli, The Thymus in Health and Senescence, 2019
There is a group of NHNP designated HMG, or “high mobility group”, that is active in histone events.213,214 HMG 17 has a distribution similar to that of H4.215 H1 cross-links with HMG14, but not with HMG 17.215,216 NHCP, a nonhistone chromatin protein, appears to interact with H2A.217 Tanaka et al. have reported on DNA-binding proteins in prokaryotes that have histone-like properties.218 In the sperm cells of man, bull, dogfish, and trout, the basic proteins associated with DNA were reportedly different from the histones of somatic cells.219 Williams et al. performed a complete amino acid sequencing of NHNP UP1, a single-strand DNA binding protein.220 It is similar to a protein that is known to destabilize DNA in mouse myeloma cells.
Cytomegalovirus (CMV) Infection
Published in Sunit K. Singh, Daniel Růžek, Neuroviral Infections, 2013
Souichi Yamada, Rumi Taniguchi, Isao Kosugi, Naoki Inoue
HCMV encodes over 200 potential open reading frames (ORFs), including 173 functional ORFs, 33 functional and HCMV-specific ORFs, and others with unknown functions. These genes are classified into immediate early (IE), early (E), and late (L) genes on the basis of their gene expression cascade. Major IE proteins encoded by UL122 and UL123 transactivate most E and L genes. E proteins, such as DNA polymerase, single-strand DNA binding protein, and helicase—primase, are required for CMV DNA replication. HCMV DNA is replicated by a rolling circle mechanism to generate multiple tandemly linked copies of the viral genome. L proteins include structural proteins for capsid, teguments, and envelope glycoproteins, and nonstructural but indispensable proteins for egress processes.
The Single-Stranded DNA Binding Protein of Bacteriophage T4
Published in James F. Kane, Multifunctional Proteins: Catalytic/Structural and Regulatory, 2019
Daniel H. Doherty, Peter Gauss, Larry Gold
We first note the effect of gp32 on a simple replication system that uses partially single-stranded lambda DNA (generated by exoIII digestion) as template and only one other protein of the T4 replication system, DNA polymerase.19 In this system (which mimics lagging-strand synthesis), gp32 stimulated DNA synthesis by the T4 DNA polymerase five to ten fold. Stimulation was greatest at low temperature and/or high salt concentration, conditions that favor intramolecular secondary structure in the template. The stimulation was interpreted as resulting from the removal of secondary structures present in the DNA template. However, denaturation of intramolecular structures is not sufficient to stimulate heterologous polymerases. The T4 single-stranded DNA binding protein does not stimulate E. coli DNA polymerase II but the E. coli single-stranded DNA binding protein (ssb gene product) does.58 This suggests that each DNA polymerase prefers single-stranded DNA with a conformation imposed by its homologous single-stranded DNA binding protein. The different contour lengths for DNA-protein bound complexes with gp32 and ssb (4.6A/nucleotide26 compared to 1.8A/nucleotide58) might reflect the base distortion required by the homologous polymerases for maximal stimulation of DNA synthesis in vitro (and perhaps in vivo). These results might also suggest that the stimulation of homologous polymerases is the result of direct protein-protein interactions between polymerase and single-stranded DNA binding protein. Such an interaction has been observed between gp32 and T4 DNA polymerase19,59 (and see below). However, we note that protein-protein complexes have not been observed betwen the T7 DNA polymerase and T7 DNA binding protein.60
LDB1-mediated transcriptional complexes are sensitive to islet stress
Published in Islets, 2022
Yanping Liu, Jessica D. Kepple, Anath Shalev, Chad S. Hunter
Our lab and others have shown that the LIM-homeodomain transcription factor, Islet-1 (ISL1), and interacting co-regulator, LIM domain-binding protein 1 (LDB1), are required for β-cell development and function.17–20 Comparative tissue- and cell-type-specific knockout mouse models revealed that LDB1:ISL1-containing complexes are necessary for β-cell development, identity, survival, and insulin secretory function via direct regulation of several key β-cell gene targets, including MafA, Pdx1, Slc2a2, Glp1r, among others.17–20 Previously published work from our lab utilizing in vitro protein interaction screens revealed the Single-Stranded DNA-Binding protein 3 (SSBP3, also called SSDP121,22) co-regulator participates in β-cell LDB1:ISL1 complexes and contributes to the regulation of MafA expression in β-cells.23 Further, ISL1 and LDB1 are maintained in human islets,19,20 highlighting the conservation and importance of these factors to mammalian β-cells and glucose homeostasis. However, little is known of whether the expression and/or interactions of ISL1 and LDB1 are modulated by β-cell stimuli or stressors.
Misconnecting the dots: altered mitochondrial protein-protein interactions and their role in neurodegenerative disorders
Published in Expert Review of Proteomics, 2020
Mara Zilocchi, Mohamed Taha Moutaoufik, Matthew Jessulat, Sadhna Phanse, Khaled A. Aly, Mohan Babu
Mt biogenesis and mitophagy are two additional mt endeavors that control mt mass and functions, and alterations of this process are also involved in NDs [3,11,23]. First, mt biogenesis implies the division of preexisting organelles through the classical trio of mtDNA replication, transcription and translation. This process accommodates increased energy demands in various brain tissues, and reports show plummeting mt biogenesis with age [98]. The DNA polymerase γ (POLG) acts together with other replisome components, such as TWINKLE mtDNA helicase (also known as PEO1), mt single-stranded DNA-binding protein (mtSSB) and mt DNA ligase III to initiate the replication of mtDNA [99]. ER-mt contact sites that are spatially linked to a subset of nucleoids and marked selectively by mtDNA polymerase are engaged with mtDNA replication and division to distribute newly replicated mtDNA in human cells, suggesting a functional interdependence between mt-ER dynamics and mt genome maintenance [79].
Hypoxia increases mutational load of breast cancer cells through frameshift mutations
Published in OncoImmunology, 2020
Goutham Hassan Venkatesh, Pamela Bravo, Walid Shaaban Moustafa Elsayed, Francis Amirtharaj, Bartosz Wojtas, Raefa Abou Khouzam, Husam Hussein Nawafleh, Sandeep Mallya, Kapaettu Satyamoorthy, Philippe Dessen, Filippo Rosselli, Jerome Thiery, Salem Chouaib
In order to further validate these data, we next evaluated the phosphorylation of histone H2A variant H2AX (γ-H2AX) at Ser139 along with the co-localization of 53BP1 which has been widely used as a sensitive marker for DNA damage especially double-stranded breaks (DSBs), as well as the expression of RPA32- a single-strand DNA binding protein used as a marker for replication stress through immunofluorescence (Supplementary figures 1 and 2). We screened at least 50 cells for at least one co-localizing foci in all the groups. The number of γ-H2AX foci alone was higher than the 53BP1 foci, irrespective of the time-points analyzed or the hypoxia treatment groups. Although we noticed an increasing trend of foci formation in chronic and intermittent hypoxia groups in comparison to normoxia, the increase was statistically insignificant (Figure 1c and d). Even after reoxygenation, there was no measurable increase in the foci.