scholarly journals Transcription of clpP Is Enhanced by a Unique Tandem Repeat Sequence in Streptococcus mutans

2008 ◽  
Vol 191 (3) ◽  
pp. 1056-1065 ◽  
Author(s):  
Jiaqin Zhang ◽  
Anirban Banerjee ◽  
Indranil Biswas
Keyword(s):  
Streptococcus Mutans ◽  
Tandem Repeat ◽  
Tandem Repeats ◽  
Single Copy ◽  
Repeat Sequence ◽  
Pcr Analysis ◽  
Gene Encoding ◽  
Tandem Repeat Sequence ◽  
Transcriptional Reporter ◽  
Reverse Transcription Pcr

ABSTRACT Streptococcus mutans, the primary causative agent of human dental caries, contains a single copy of the gene encoding ClpP, the chief intracellular protease responsible for tolerance to various environmental stresses. To better understand the role of ClpP in stress response, we investigated the regulation of clpP expression in S. mutans. Using semiquantitative reverse transcription-PCR analysis, we observed that, under nonstressed conditions, clpP expression is somewhat constant throughout the growth phases, although it gradually decreases as cells enter the late stationary phase. The half-life of the clpP transcript was found to be less than 1 minute. Sequence analysis of the clpP locus reveals the presence of a 50-bp tandem repeat sequence located immediately upstream of the clpP promoter (PclpP). PCR and DNA sequence analyses suggest that the number of tandem repeat units can vary from as few as two to as many as nine, depending on the particular S. mutans isolate. Further analysis, using a transcriptional reporter fusion consisting of PclpP fused to a promoterless gusA gene, indicates that the presence of the repeat sequence region within PclpP results in an approximately fivefold increase in expression from PclpP compared to the repeat-free transcriptional reporter fusion. CtsR, a transcriptional repressor that negatively regulates clpP expression, has no effect on this repeat-mediated induction of clpP transcription. Furthermore, the repeat sequence is not necessary for the induction of clpP under stress conditions. Database searches indicate that the region containing the tandem repeats is absent in the clpP loci in other bacteria, including other closely related Streptococcus spp., suggesting that the repeat sequences are specific for the induction of clpP expression in S. mutans. We speculate that a host-specific transcriptional activator might be involved in the upregulation of clpP expression in S. mutans.

Synthesis of MUC1 Peptide and Glycopeptide Dendrimers

2009 ◽  
Vol 62 (10) ◽  
pp. 1339 ◽  
Author(s):  
Candy K. Y. Chun ◽  
Richard J. Payne
Keyword(s):  
Peptide Synthesis ◽  
Tandem Repeat ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Cycloaddition Reaction ◽  
Repeat Sequence ◽  
Tandem Repeat Sequence ◽  
Multiple Copies ◽  
Fmoc Strategy

Several dendrimers possessing multiple copies of peptides and glycopeptides belonging to the MUC1 eicosapeptide tandem repeat sequence have been prepared. Fmoc-strategy solid-phase peptide synthesis was used to construct the peptides and glycopeptides, which were conjugated to suitably functionalized dendrimer cores using the copper-catalyzed azide-alkyne cycloaddition reaction to produce multivalent peptide and glycopeptide dendrimers.

scholarly journals New Tools for Hop Cytogenomics: Identification of Tandem Repeat Families from Long-Read Sequences of Humulus lupulus

2020 ◽  
Author(s):  
Katherine A. Easterling ◽  
Nicholi J. Pitra ◽  
Taylan B. Morcol ◽  
Jenna R. Aquino ◽  
Lauren G. Lopes ◽  
...  
Keyword(s):  
Tandem Repeat ◽  
Mendelian Inheritance ◽  
Repeat Sequence ◽  
Humulus Lupulus ◽  
Comparative Genomic ◽  
Dioecious Species ◽  
Tandem Repeat Sequence ◽  
Genome Maps ◽  
Meiotic Chromosomes ◽  
Long Read

ABSTRACTHop (Humulus lupulus L.) is known for its use as a bittering agent in beer and has a rich history of cultivation, beginning in Europe and now spanning the globe. There are five wild varieties worldwide, which may have been introgressed with cultivated varieties. As a dioecious species, its obligate outcrossing, non-Mendelian inheritance, and genomic structural variability have confounded directed breeding efforts. Consequently, understanding genome evolution in Humulus represents a considerable challenge, requiring additional resources, including integrated genome maps. In order to facilitate cytogenetic investigations into the transmission genetics of hop, we report here the identification and characterization of 17 new and distinct tandem repeat sequence families. A tandem repeat discovery pipeline was developed using k-mer filtering and dot plot analysis of PacBio long-read sequences from the hop cultivar Apollo. We produced oligonucleotide FISH probes from conserved regions of HuluTR120 and HulTR225 and demonstrated their utility to stain meiotic chromosomes from wild hop, var. neomexicanus. The HuluTR225 FISH probe hybridized to several loci per nucleus and exhibited irregular, non-Mendelian transmission in male meiocytes of wild hop. Collectively, these tandem repeat sequence families not only represent unique and valuable new cytogenetic reagents but also have the capacity to inform genome assembly efforts and support comparative genomic analyses.

scholarly journals The Erwinia chrysanthemi 3937 PhoQ Sensor Kinase Regulates Several Virulence Determinants

2006 ◽  
Vol 188 (8) ◽  
pp. 3088-3098 ◽  
Author(s):  
Balakrishnan Venkatesh ◽  
Lavanya Babujee ◽  
Hui Liu ◽  
Pete Hedley ◽  
Takashi Fujikawa ◽  
...  
Keyword(s):  
Virulence Factors ◽  
Regulatory System ◽  
Soft Rot ◽  
Erwinia Chrysanthemi ◽  
Pcr Analysis ◽  
Sensor Kinase ◽  
Virulence Determinants ◽  
Gene Encoding ◽  
Reverse Transcription Pcr ◽  
Two Component

ABSTRACT The PhoPQ two-component system regulates virulence factors in Erwinia chrysanthemi, a pectinolytic enterobacterium that causes soft rot in several plant species. We characterized the effect of a mutation in phoQ, the gene encoding the sensor kinase PhoQ of the PhoPQ two-component regulatory system, on the global transcriptional profile of E. chrysanthemi using cDNA microarrays and further confirmed our results by quantitative reverse transcription-PCR analysis. Our results indicate that a mutation in phoQ affects transcription of at least 40 genes, even in the absence of inducing conditions. Enhanced expression of several genes involved in iron metabolism was observed in the mutant, including that of the acs operon that is involved in achromobactin biosynthesis and transport. This siderophore is required for full virulence of E. chrysanthemi, and its expression is governed by the global repressor protein Fur. Changes in gene expression were also observed for membrane transporters, stress-related genes, toxins, and transcriptional regulators. Our results indicate that the PhoPQ system governs the expression of several additional virulence factors and may also be involved in interactions with other regulatory systems.

An extra insertion of tandem repeat sequence in African swine fever virus, China, 2019

Virus Genes ◽  
2019 ◽  
Vol 55 (6) ◽  
pp. 843-847 ◽  
Author(s):  
Shengqiang Ge ◽  
Yutian Liu ◽  
Lin Li ◽  
Qinghua Wang ◽  
Jinming Li ◽  
...  
Keyword(s):  
Tandem Repeat ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Repeat Sequence ◽  
Fever Virus ◽  
Tandem Repeat Sequence

Study on Tandem Repeat Sequence Variation in Sheep mtDNA D-loop Region

2006 ◽  
Vol 33 (12) ◽  
pp. 1087-1095 ◽  
Author(s):  
LI Xiang-Long ◽  
GONG Yuan-Fang ◽  
LIU Zheng-Zhu ◽  
ZHENG Gui-Ru ◽  
ZHOU Rong-Yan ◽  
...  
Keyword(s):  
Tandem Repeat ◽  
Sequence Variation ◽  
Repeat Sequence ◽  
Tandem Repeat Sequence ◽  
Loop Region ◽  
D Loop
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