scholarly journals DNA replication in chloroplasts

1993 ◽  
Vol 104 (1) ◽  
pp. 1-9 ◽  
Author(s):  
S. Heinhorst ◽  
G.C. Cannon
Keyword(s):  
Dna Replication ◽  
Chloroplast Dna ◽  
Molecular Basis ◽  
Copy Number ◽  
Molecular Level ◽  
Gene Products ◽  
Biochemical Mechanism ◽  
Dna Molecule ◽  
Multiple Copies ◽  
Present Understanding

Chloroplasts contain multiple copies of a DNA molecule (the plastome) that encodes many of the gene products required to perform photosynthesis. The plastome is replicated by nuclear-encoded proteins and its copy number seems to be highly regulated by the cell in a tissue-specific and developmental manner. Our understanding of the biochemical mechanism by which the plastome is replicated and the molecular basis for its regulation is limited. In this commentary we review our present understanding of chloroplast DNA replication and examine current efforts to elucidate its mechanism at a molecular level.

scholarly journals Yeast nuclear PET127 gene can suppress deletions of the SUV3 or DSS1 genes: an indication of a functional interaction between 3' and 5' ends of mitochondrial mRNAs.

1998 ◽  
Vol 45 (4) ◽  
pp. 935-940 ◽  
Author(s):  
T Wegierski ◽  
A Dmochowska ◽  
A Jabłonowska ◽  
A Dziembowski ◽  
E Bartnik ◽  
...  
Keyword(s):  
Copy Number ◽  
Molecular Level ◽  
Nuclear Gene ◽  
Functional Coupling ◽  
Mitochondrial Rna ◽  
Gene Products ◽  
Mitochondrial Translation ◽  
Functional Interaction ◽  
Negative Phenotype

Saccharomyces cerevisiae nuclear genes SUV3 and DSS1 encode putative RNA helicase and RNase II, respectively, which are subunits of the mitochondrial degradosome (mtEXO): a three-protein complex which has a 3' to 5' exoribonuclease activity and plays a major role in regulating stability of mitochondrial RNA. Lack of either of the two gene products results in a respiratory negative phenotype, while on the molecular level it causes a total block of mitochondrial translation, loss of the in vitro exoribonuclease activity and changes in stability and processing of many mtRNAs. We have found that the yeast nuclear gene PET127 present on a low or high copy number vector can effectively suppress the effects of the SUV3 or DSS1 gene disruptions. Since the product of the PET127 gene is involved in processing of the 5' ends of mitochondrial mRNAs, we suggest that there is a functional coupling between the 5' and 3' ends of mitochondrial mRNAs.

scholarly journals Effect of multiple copies ofrpoBCon the rate of RNA synthesis inEscherichia coli

1986 ◽  
Vol 48 (2) ◽  
pp. 61-64 ◽  
Author(s):  
Elena C. Guzman ◽  
Alfonso Jimenez-Sanchez
Keyword(s):  
Dna Replication ◽  
Rna Polymerase ◽  
Rna Synthesis ◽  
Synthetic Activity ◽  
Gene Products ◽  
Replication Forks ◽  
E Coli ◽  
Multiple Copies ◽  
Autogenous Regulation ◽  
Rate Of Movement

SummaryThe cloning of therpoBandrpoCgenes in a high copy number vector inE. coliincreased the amount of the encoded gene products, the β and β′ subunits of RNA polymerase. However, this unexpectedly caused a 30–50% decrease in RNA synthetic activity which alternatively induced a reduction of growth rate and enlargement of cell size, and decreased the DNA replication time. The results can be explained by autogenous regulation of the RNA polymerase genes by the ββ′ subunits. A relation between the decrease in number of transcription units and the observed higher rate of movement of DNA replication forks is discussed.

scholarly journals Improvement and Optimization of Two Engineered Phage Resistance Mechanisms in Lactococcus lactis

2001 ◽  
Vol 67 (2) ◽  
pp. 608-616 ◽  
Author(s):  
Stephen McGrath ◽  
Gerald F. Fitzgerald ◽  
Douwe van Sinderen
Keyword(s):  
Dna Replication ◽  
Sequence Analysis ◽  
Copy Number ◽  
Resistance Mechanisms ◽  
Phage Resistance ◽  
Dna Homology ◽  
Effective Strategies ◽  
Phage Dna ◽  
Multiple Copies ◽  
Replication Module

ABSTRACT Homologous replication module genes were identified for four P335 type phages. DNA sequence analysis revealed that all four phages exhibited more than 90% DNA homology for at least two genes, designated rep2009 and orf17. One of these genes, rep2009 , codes for a putative replisome organizer protein and contains an assumed origin of phage DNA replication (ori2009 ), which was identical for all four phages. DNA fragments representing theori2009 sequence confer a phage-encoded resistance (Per) phenotype on lactococcal hosts when they are supplied on a high-copy-number vector. Furthermore, cloning multiple copies of the ori2009 sequence was found to increase the effectiveness of the Per phenotype conferred. A number of antisense plasmids targeting specific genes of the replication module were constructed. Two separate plasmids targetingrep2009 and orf17 were found to efficiently inhibit proliferation of all four phages by interfering with intracellular phage DNA replication. These results represent two highly effective strategies for inhibiting bacteriophage proliferation, and they also identify a novel gene, orf17, which appears to be important for phage DNA replication. Furthermore, these results indicate that although the actual mechanisms of DNA replication are very similar, if not identical, for all four phages, expression of the replication genes is significantly different in each case.

scholarly journals Recent Advances in the Chemical Biology of N-Glycans

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1040
Author(s):  
Asuka Shirakawa ◽  
Yoshiyuki Manabe ◽  
Koichi Fukase
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Molecular Basis ◽  
Chemical Biology ◽  
Molecular Level ◽  
Chemoenzymatic Synthesis ◽  
Complex Structures ◽  
Recent Advances ◽  
Protein Functions ◽  
Potential Applications

Asparagine-linked N-glycans on proteins have diverse structures, and their functions vary according to their structures. In recent years, it has become possible to obtain high quantities of N-glycans via isolation and chemical/enzymatic/chemoenzymatic synthesis. This has allowed for progress in the elucidation of N-glycan functions at the molecular level. Interaction analyses with lectins by glycan arrays or nuclear magnetic resonance (NMR) using various N-glycans have revealed the molecular basis for the recognition of complex structures of N-glycans. Preparation of proteins modified with homogeneous N-glycans revealed the influence of N-glycan modifications on protein functions. Furthermore, N-glycans have potential applications in drug development. This review discusses recent advances in the chemical biology of N-glycans.

Polyomavirus enhancer contains multiple redundant sequence elements that activate both DNA replication and gene expression

1985 ◽  
Vol 5 (4) ◽  
pp. 649-658
Author(s):  
G M Veldman ◽  
S Lupton ◽  
R Kamen
Keyword(s):  
Dna Replication ◽  
Globin Gene ◽  
Mrna Levels ◽  
Beta Globin ◽  
Transcriptional Enhancer ◽  
Globin Mrna ◽  
Enhancer Region ◽  
Sequence Elements ◽  
Multiple Copies ◽  
A Site

Sequences that comprise the 244-base-pair polyomavirus enhancer region are also required in cis for viral DNA replication (Tyndall et al., Nucleic Acids Res. 9:6231-6250, 1981). We have studied the relationship between the sequences that activate replication and those that enhance transcription in two ways. One approach, recently described by de Villiers et al. (Nature [London], 312:242-246, 1984), in which the polyomavirus enhancer region was replaced with other viral or cellular transcriptional enhancers suggested that an enhancer function is required for polyomavirus DNA replication. The other approach, described in this paper, was to analyze a series of deletion mutants that functionally dissect the enhancer region and enabled us to localize four sequence elements in this region that are involved in the activation of replication. These elements, which have little sequence homology, are functionally redundant. Element A (nucleotides 5108 through 5130) was synthesized as a 26-mer with XhoI sticky ends, and one or more copies were introduced into a plasmid containing the origin of replication, but lacking the enhancer region. Whereas one copy of the 26-mer activated replication only to 2 to 5% of the wild-type level, two copies inserted in either orientation completely restored replication. We found that multiple copies of the 26-mer were also active as a transcriptional enhancer by measuring the beta-globin mRNA levels expressed from a plasmid that contained either the polyomavirus enhancer or one or more copies of the 26-mer inserted in a site 3' to the beta-globin gene. We observed a correlation between the number of inserted 26-mers and the level of beta-globin RNA expression.

scholarly journals Clinical and Molecular Evaluation of SHOX/PAR1 Duplications in Léri-Weill Dyschondrosteosis (LWD) and Idiopathic Short Stature (ISS)

2011 ◽  
Vol 96 (2) ◽  
pp. E404-E412 ◽  
Author(s):  
S. Benito-Sanz ◽  
E. Barroso ◽  
D. Heine-Suñer ◽  
A. Hisado-Oliva ◽  
V. Romanelli ◽  
...  
Keyword(s):  
Short Stature ◽  
Skeletal Dysplasia ◽  
Copy Number ◽  
Clinical Manifestations ◽  
Idiopathic Short Stature ◽  
Pseudoautosomal Region ◽  
Height Gain ◽  
Multiple Copies ◽  
Copy Number Changes ◽  
Design And Methods

abstract Context: Léri-Weill dyschondrosteosis (LWD) is a skeletal dysplasia characterized by disproportionate short stature and the Madelung deformity of the forearm. SHOX mutations and pseudoautosomal region 1 deletions encompassing SHOX or its enhancers have been identified in approximately 60% of LWD and approximately 15% of idiopathic short stature (ISS) individuals. Recently SHOX duplications have been described in LWD/ISS but also in individuals with other clinical manifestations, thus questioning their pathogenicity. Objective: The objective of the study was to investigate the pathogenicity of SHOX duplications in LWD and ISS. Design and Methods: Multiplex ligation-dependent probe amplification is routinely used in our unit to analyze for SHOX/pseudoautosomal region 1 copy number changes in LWD/ISS referrals. Quantitative PCR, microsatellite marker, and fluorescence in situ hybridization analysis were undertaken to confirm all identified duplications. Results: During the routine analysis of 122 LWD and 613 ISS referrals, a total of four complete and 10 partial SHOX duplications or multiple copy number (n > 3) as well as one duplication of the SHOX 5′ flanking region were identified in nine LWD and six ISS cases. Partial SHOX duplications appeared to have a more deleterious effect on skeletal dysplasia and height gain than complete SHOX duplications. Importantly, no increase in SHOX copy number was identified in 340 individuals with normal stature or 104 overgrowth referrals. Conclusion: MLPA analysis of SHOX/PAR1 led to the identification of partial and complete SHOX duplications or multiple copies associated with LWD or ISS, suggesting that they may represent an additional class of mutations implicated in the molecular etiology of these clinical entities.

Replication from a proximal simian virus 40 origin is severely inhibited by multiple reiterations of the 72-base-pair repeat enhancer sequence

1988 ◽  
Vol 8 (4) ◽  
pp. 1509-1517
Author(s):  
R Kumar ◽  
K P Yoon ◽  
K N Subramanian
Keyword(s):  
Transcriptional Activation ◽  
Base Pair ◽  
Copy Number ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Origin Of Replication ◽  
Replication Efficiency ◽  
Sv40 Origin ◽  
Multiple Copies ◽  
In Cis

In a previous study in our laboratory, the effect of the reiteration frequency of the simian virus 40 (SV40) 72-base-pair (bp) repeat enhancer on transcription from the proximal SV40 early promoter was investigated (R. Kumar, T. A. Firak, C. T. Schroll, and K. N. Subramanian, Proc. Natl. Acad. Sci. USA 83:3199-3203, 1986). Increasing the enhancer copy number to four increased transcription proportionately; further increments in enhancer copy number reversed this effect, resulting in a decrease in the transcriptional activation. In the present study, the effect of enhancer reiteration on the replication efficiency of plasmids containing the SV40 origin of replication was investigated in transient replication assays in vivo in COS-1 monkey kidney cells producing the SV40 large tumor antigen required for replication. A plasmid containing the SV40 core origin and three copies of the replication-activating, G+C-rich 21-bp repeat promoter element replicated efficiently. Plasmids containing multiple copies of the 72-bp repeat enhancer cloned in head-to-tail linkage adjacent to the 21-bp repeat and the core origin replicated less efficiently; the decrease in replication efficiency could be correlated with the number of copies of the 72-bp repeat; replication was severely curtailed when 10 or more copies of the 72-bp repeat were present. Replication was not significantly inhibited by an increase in the number of copies of the 21-bp repeat to 15 or by the presence of three copies of a 360-bp pBR322 sequence in the immediate vicinity. Multiple copies of the 72-bp enhancer in cis were unable to inhibit replication from a second SV40 origin of replication situated 2 kilobase pairs away from the enhancer reiteration. Replication of four different test plasmids was not inhibited in trans by cotransfection of an excess of a potential competitor plasmid containing a 24-copy reiteration of the 72-bp enhancer. These results indicate that multiple tandem reiterations of the 72-bp enhancer inhibit replication only when they are present in cis adjacent to the origin of replication. Possible explanations for this inhibitory effect, such as an unfavorable local chromatin structure induced by the multimeric enhancer region or reduced or improper communications between factors bound to the multimeric region and the adjacent replication origin, are discussed.

Mitochondrial DNA replication is initiated at blastocyst formation in equine embryos

2019 ◽  
Vol 31 (3) ◽  
pp. 570 ◽  
Author(s):  
W. Karin Hendriks ◽  
Silvia Colleoni ◽  
Cesare Galli ◽  
Damien B. B. P. Paris ◽  
Ben Colenbrander ◽  
...  
Keyword(s):  
Dna Replication ◽  
Copy Number ◽  
Oocyte Quality ◽  
Culture Conditions ◽  
Developmental Competence ◽  
Mtdna Copy Number ◽  
Blastocyst Development ◽  
Mt Dna ◽  
Mitochondrial Transcription Factor ◽  
Mitochondrial Number

Intracytoplasmic sperm injection is the technique of choice for equine IVF and, in a research setting, 18–36% of injected oocytes develop to blastocysts. However, blastocyst development in clinical programs is lower, presumably due to a combination of variable oocyte quality (e.g. from old mares), suboptimal culture conditions and marginal fertility of some stallions. Furthermore, mitochondrial constitution appears to be critical to developmental competence, and both maternal aging and invitro embryo production (IVEP) negatively affect mitochondrial number and function in murine and bovine embryos. The present study examined the onset of mitochondrial (mt) DNA replication in equine embryos and investigated whether IVEP affects the timing of this important event, or the expression of genes required for mtDNA replication (i.e. mitochondrial transcription factor (TFAM), mtDNA polymerase γ subunit B (mtPOLB) and single-stranded DNA binding protein (SSB)). We also investigated whether developmental arrest was associated with low mtDNA copy number. mtDNA copy number increased (P<0.01) between the early and expanded blastocyst stages both invivo and invitro, whereas the mtDNA:total DNA ratio was higher in invitro-produced embryos (P=0.041). Mitochondrial replication was preceded by an increase in TFAM but, unexpectedly, not mtPOLB or SSB expression. There was no association between embryonic arrest and lower mtDNA copy numbers.

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