scholarly journals PolB1 Is Sufficient for DNA Replication and Repair Under Normal Growth Conditions in the Extremely Thermophilic Crenarchaeon Sulfolobus acidocaldarius

2020 ◽  
Vol 11 ◽  
Author(s):  
Hiroka Miyabayashi ◽  
Rupal Jain ◽  
Shoji Suzuki ◽  
Dennis W. Grogan ◽  
Norio Kurosawa

The thermophilic crenarchaeon Sulfolobus acidocaldarius has four DNA polymerases (DNAPs): PolB1, PolB2, PolB3, and Dbh (PolY). Previous in vitro studies suggested that PolB1 is the main replicative DNAP of Sulfolobales whereas PolB2 and Y-family polymerases Dpo4 (Saccharolobus solfataricus) or Dbh are involved in DNA repair and translesion DNA synthesis. On the other hand, there are various opinions about the role of PolB3, which remains to be clearly resolved. In order to examine the roles of the DNAPs of S. acidocaldarius through in vivo experiments, we constructed polB2, polB3, and dbh deletion strains and characterized their phenotypes. Efforts to construct a polB1 deletion strain were not successful; in contrast, it was possible to isolate triple gene-deletion strains lacking polB2, polB3, and dbh. The growth of these strains was nearly the same as that of the parent strains under normal growth conditions. The polB2, polB3, and dbh single-deletion strains were sensitive to some types of DNA-damaging treatments, but exhibited normal sensitivity to UV irradiation and several other damaging treatments. Overall, the genotype which exhibited the greatest sensitivity to the DNA-damaging treatments we tested was the ΔpolB2 ΔpolB3 combination, providing the first evidence of overlapping function for these two DNAPs in vivo. The results of our study strongly suggest that PolB1 is responsible for the DNA replication of both the leading and lagging strands and is sufficient to complete the repair of most DNA damage under normal growth conditions in S. acidocaldarius.

2006 ◽  
Vol 26 (16) ◽  
pp. 6117-6129 ◽  
Author(s):  
Kimberly C. Lindstrom ◽  
Jay C. Vary ◽  
Mark R. Parthun ◽  
Jeffrey Delrow ◽  
Toshio Tsukiyama

ABSTRACT The packaging of DNA into chromatin allows eukaryotic cells to organize and compact their genomes but also creates an environment that is generally repressive to nuclear processes that depend upon DNA accessibility. There are several classes of enzymes that modulate the primary structure of chromatin to regulate various DNA-dependent processes. The biochemical activities of the yeast Isw1 ATP-dependent chromatin-remodeling enzyme have been well characterized in vitro, but little is known about how these activities are utilized in vivo. In this work, we sought to discern genetic backgrounds that require Isw1 activity for normal growth. We identified a three-way genetic interaction among Isw1, the NuA4 histone acetyltransferase complex, and the Swr1 histone replacement complex. Transcription microarray analysis revealed parallel functions for these three chromatin-modifying factors in the regulation of TATA-containing genes, including the repression of a large number of stress-induced genes under normal growth conditions. In contrast to a recruitment-based model, we find that the NuA4 and Swr1 complexes act throughout the genome while only a specific subset of the genome shows alterations in transcription.


2005 ◽  
Vol 170 (7) ◽  
pp. 1091-1099 ◽  
Author(s):  
Jessica E. Smotrys ◽  
Marissa J. Schoenfish ◽  
Monica A. Stutz ◽  
Maurine E. Linder

Palmitoylation of the vacuolar membrane protein Vac8p is essential for vacuole fusion in yeast (Veit, M., R. Laage, L. Dietrich, L. Wang, and C. Ungermann. 2001. EMBO J. 20:3145–3155; Wang, Y.X., E.J. Kauffman, J.E. Duex, and L.S. Weisman. 2001. J. Biol. Chem. 276:35133–35140). Proteins that contain an Asp-His-His-Cys (DHHC)–cysteine rich domain (CRD) are emerging as a family of protein acyltransferases, and are therefore candidates for mediators of Vac8p palmitoylation. Here we demonstrate that the DHHC-CRD proteins Pfa3p (protein fatty acyltransferase 3, encoded by YNL326c) and Swf1p are important for vacuole fusion. Cells lacking Pfa3p had fragmented vacuoles when stressed, and cells lacking both Pfa3p and Swf1p had fragmented vacuoles under normal growth conditions. Pfa3p promoted Vac8p membrane association and palmitoylation in vivo and partially purified Pfa3p palmitoylated Vac8p in vitro, establishing Vac8p as a substrate for palmitoylation by Pfa3p. Vac8p is the first N-myristoylated, palmitoylated protein identified as a substrate for a DHHC-CRD protein.


2021 ◽  
Vol 118 (8) ◽  
pp. e2017497118
Author(s):  
Guangxue Liu ◽  
Jiaqi Yan ◽  
Xuejie Wang ◽  
Junliang Chen ◽  
Xin Wang ◽  
...  

The ubiquitin E3 ligase Bre1-mediated H2B monoubiquitination (H2Bub) is essential for proper DNA replication and repair in eukaryotes. Deficiency in H2Bub causes genome instability and cancer. How the Bre1–H2Bub pathway is evoked in response to DNA replication or repair remains unknown. Here, we identify that the single-stranded DNA (ssDNA) binding factor RPA acts as a key mediator that couples Bre1-mediated H2Bub to DNA replication and repair in yeast. We found that RPA interacts with Bre1 in vitro and in vivo, and this interaction is stimulated by ssDNA. This association ensures the recruitment of Bre1 to replication forks or DNA breaks but does not affect its E3 ligase activity. Disruption of the interaction abolishes the local enrichment of H2Bub, resulting in impaired DNA replication, response to replication stress, and repair by homologous recombination, accompanied by increased genome instability and DNA damage sensitivity. Notably, we found that RNF20, the human homolog of Bre1, interacts with RPA70 in a conserved mode. Thus, RPA functions as a master regulator for the spatial–temporal control of H2Bub chromatin landscape during DNA replication and recombination, extending the versatile roles of RPA in guarding genome stability.


1998 ◽  
Vol 180 (9) ◽  
pp. 2395-2401 ◽  
Author(s):  
Franz Narberhaus ◽  
Michael Kowarik ◽  
Christoph Beck ◽  
Hauke Hennecke

ABSTRACT Expression of the dnaKJ andgroESL 1 heat shock operons ofBradyrhizobium japonicum depends on a ς32-like transcription factor. Three such factors (RpoH1, RpoH2, and RpoH3) have previously been identified in this organism. We report here that they direct transcription from some but not all ς32-type promoters when the respective rpoH genes are expressed inEscherichia coli. All three RpoH factors were purified as soluble C-terminally histidine-tagged proteins, although the bulk of overproduced RpoH3 was insoluble. The purified proteins were recognized by an anti-E. coli ς32 serum. While RpoH1 and RpoH2 productively interacted with E. coli core RNA polymerase and produced E. coli groE transcript in vitro, RpoH3 was unable to do so.B. japonicum core RNA polymerase was prepared and reconstituted with the RpoH proteins. Again, RpoH1 and RpoH2 were active, and they initiated transcription at theB. japonicum groESL 1 and dnaKJpromoters. In all cases, the in vitro start site was shown to be identical to the start site determined in vivo. Promoter competition experiments revealed that the B. japonicum dnaKJ andgroESL 1 promoters were suboptimal for transcription by RpoH1- or RpoH2-containing RNA polymerase from B. japonicum. In a mixture of different templates, the E. coli groESL promoter was preferred over any other promoter. Differences were observed in the specificities of both sigma factors toward B. japonicum rpoH-dependent promoters. We conclude that the primary function of RpoH2is to supply the cell with DnaKJ under normal growth conditions whereas RpoH1 is responsible mainly for increasing the level of GroESL1 after a heat shock.


BioEssays ◽  
2021 ◽  
Vol 43 (5) ◽  
pp. 2000309
Author(s):  
Jorge B. Schvartzman ◽  
Víctor Martínez ◽  
Pablo Hernández ◽  
Dora B. Krimer ◽  
María‐José Fernández‐Nestosa

2005 ◽  
Vol 79 (13) ◽  
pp. 8661-8664 ◽  
Author(s):  
Stephen Schuck ◽  
Arne Stenlund

ABSTRACT Viral initiator proteins are polypeptides that form oligomeric complexes on the origin of DNA replication (ori). These complexes carry out a multitude of functions related to initiation of DNA replication, and although many of these functions have been characterized biochemically, little is understood about how the complexes are assembled. Here we demonstrate that loss of one particular interaction, the dimerization between E1 DNA binding domains, has a severe effect on DNA replication in vivo but has surprisingly modest effects on most individual biochemical activities in vitro. We conclude that the dimer interaction is primarily required for initial recognition of ori.


2001 ◽  
Vol 12 (5) ◽  
pp. 1199-1213 ◽  
Author(s):  
Gregory G. Oakley ◽  
Lisa I. Loberg ◽  
Jiaqin Yao ◽  
Mary A. Risinger ◽  
Remy L. Yunker ◽  
...  

Exposure to DNA-damaging agents triggers signal transduction pathways that are thought to play a role in maintenance of genomic stability. A key protein in the cellular processes of nucleotide excision repair, DNA recombination, and DNA double-strand break repair is the single-stranded DNA binding protein, RPA. We showed previously that the p34 subunit of RPA becomes hyperphosphorylated as a delayed response (4–8 h) to UV radiation (10–30 J/m2). Here we show that UV-induced RPA-p34 hyperphosphorylation depends on expression of ATM, the product of the gene mutated in the human genetic disorder ataxia telangiectasia (A-T). UV-induced RPA-p34 hyperphosphorylation was not observed in A-T cells, but this response was restored by ATM expression. Furthermore, purified ATM kinase phosphorylates the p34 subunit of RPA complex in vitro at many of the same sites that are phosphorylated in vivo after UV radiation. Induction of this DNA damage response was also dependent on DNA replication; inhibition of DNA replication by aphidicolin prevented induction of RPA-p34 hyperphosphorylation by UV radiation. We postulate that this pathway is triggered by the accumulation of aberrant DNA replication intermediates, resulting from DNA replication fork blockage by UV photoproducts. Further, we suggest that RPA-p34 is hyperphosphorylated as a participant in the recombinational postreplication repair of these replication products. Successful resolution of these replication intermediates reduces the accumulation of chromosomal aberrations that would otherwise occur as a consequence of UV radiation.


2001 ◽  
Vol 69 (6) ◽  
pp. 4079-4085 ◽  
Author(s):  
Sarah E. Cramton ◽  
Martina Ulrich ◽  
Friedrich Götz ◽  
Gerd Döring

ABSTRACT Products of the intercellular adhesion (ica) operon in Staphylococcus aureus and Staphylococcus epidermidis synthesize a linear β-1,6-linked glucosaminylglycan. This extracellular polysaccharide mediates bacterial cell-cell adhesion and is required for biofilm formation, which is thought to increase the virulence of both pathogens in association with prosthetic biomedical implants. The environmental signal(s) that triggers ica gene product and polysaccharide expression is unknown. Here we demonstrate that anaerobic in vitro growth conditions lead to increased polysaccharide expression in both S. aureus and S. epidermidis, although the regulation is less stringent inS. epidermidis. Anaerobiosis also dramatically stimulates ica-specific mRNA expression inica- and polysaccharide-positive strains of both S. aureus and S. epidermidis.These data suggest a mechanism whereby ica gene expression and polysaccharide production may act as a virulence factor in an anaerobic environment in vivo.


Genetics ◽  
1998 ◽  
Vol 148 (3) ◽  
pp. 989-1005 ◽  
Author(s):  
Keiko Umezu ◽  
Neal Sugawara ◽  
Clark Chen ◽  
James E Haber ◽  
Richard D Kolodner

Abstract Replication protein A (RPA) is a single-stranded DNA-binding protein identified as an essential factor for SV40 DNA replication in vitro. To understand the in vivo functions of RPA, we mutagenized the Saccharomyces cerevisiae RFA1 gene and identified 19 ultraviolet light (UV) irradiation- and methyl methane sulfonate (MMS)-sensitive mutants and 5 temperature-sensitive mutants. The UV- and MMS-sensitive mutants showed up to 104 to 105 times increased sensitivity to these agents. Some of the UV- and MMS-sensitive mutants were killed by an HO-induced double-strand break at MAT. Physical analysis of recombination in one UV- and MMS-sensitive rfa1 mutant demonstrated that it was defective for mating type switching and single-strand annealing recombination. Two temperature-sensitive mutants were characterized in detail, and at the restrictive temperature were found to have an arrest phenotype and DNA content indicative of incomplete DNA replication. DNA sequence analysis indicated that most of the mutations altered amino acids that were conserved between yeast, human, and Xenopus RPA1. Taken together, we conclude that RPA1 has multiple roles in vivo and functions in DNA replication, repair, and recombination, like the single-stranded DNA-binding proteins of bacteria and phages.


1987 ◽  
Vol 7 (10) ◽  
pp. 3694-3704
Author(s):  
C Prives ◽  
Y Murakami ◽  
F G Kern ◽  
W Folk ◽  
C Basilico ◽  
...  

Cell extracts of FM3A mouse cells replicate polyomavirus (Py) DNA in the presence of immunoaffinity-purified Py large T antigen, deoxynucleoside triphosphates, ATP, and an ATP-generating system. This system was used to examine the effects of mutations within or adjacent to the Py core origin (ori) region in vitro. The analysis of plasmid DNAs containing deletions within the early-gene side of the Py core ori indicated that sequences between nucleotides 41 and 57 define the early boundary of Py DNA replication in vitro. This is consistent with previously published studies on the early-region sequence requirements for Py replication in vivo. Deleting portions of the T-antigen high-affinity binding sites A and B (between nucleotides 57 and 146) on the early-gene side of the core ori led to increased levels of replication in vitro and to normal levels of replication in vivo. Point mutations within the core ori region that abolish Py DNA replication in vivo also reduced replication in vitro. A mutant with a reversed orientation of the Py core ori region replicated in vitro, but to a lesser extent that wild-type Py DNA. Plasmids with deletions on the late-gene side of the core ori, within the enhancer region, that either greatly reduced or virtually abolished Py DNA replication in vivo replicated to levels similar to those of wild-type Py DNA plasmids in vitro. Thus, as has been observed with simian virus 40, DNA sequences needed for Py replication in vivo are different from and more stringent than those required in vitro.


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