共查询到20条相似文献,搜索用时 125 毫秒
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Arancha Catalan-Moreno Marta Cela Pilar Menendez-Gil Naiara Irurzun Carlos
J Caballero Isabelle Caldelari Alejandro Toledo-Arana 《Nucleic acids research》2021,49(6):3409
Thermoregulation of virulence genes in bacterial pathogens is essential for environment-to-host transition. However, the mechanisms governing cold adaptation when outside the host remain poorly understood. Here, we found that the production of cold shock proteins CspB and CspC from Staphylococcus aureus is controlled by two paralogous RNA thermoswitches. Through in silico prediction, enzymatic probing and site-directed mutagenesis, we demonstrated that cspB and cspC 5′UTRs adopt alternative RNA structures that shift from one another upon temperature shifts. The open (O) conformation that facilitates mRNA translation is favoured at ambient temperatures (22°C). Conversely, the alternative locked (L) conformation, where the ribosome binding site (RBS) is sequestered in a double-stranded RNA structure, is folded at host-related temperatures (37°C). These structural rearrangements depend on a long RNA hairpin found in the O conformation that sequesters the anti-RBS sequence. Notably, the remaining S. aureus CSP, CspA, may interact with a UUUGUUU motif located in the loop of this long hairpin and favour the folding of the L conformation. This folding represses CspB and CspC production at 37°C. Simultaneous deletion of the cspB/cspC genes or their RNA thermoswitches significantly decreases S. aureus growth rate at ambient temperatures, highlighting the importance of CspB/CspC thermoregulation when S. aureus transitions from the host to the environment. 相似文献
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Sang Jun Lee Aiguo Xie Weining Jiang Jean-Pierre Etchegaray Pamela G. Jones Masayori Inouye 《Molecular microbiology》1994,11(5):833-839
The cspA is a gene of Escherichia coli, whose expression is specifically induced at low temperatures to a level of 13% of total protein synthesis. The CspA protein consisting of 70 amino add residues has high sequence similarity with eukaryotic Y-box DNA-binding proteins. We found two independent clones from the Kohara miniset phage collection, which hybridized with a DNA fragment containing cspA. DNA sequencing of these clones confirmed that the two genes are highly homologous to cspA. One designated cspB is mapped at 35 min on the E. coli chromosome and encodes a 71-residue protein with 79% identity to CspA, while the other, cspC, is mapped at 40 min and encodes a 69-residue protein with 70% identity. In addition, a DNA sequence upstream of the clpA gene at 19 mm published elsewhere contains an open reading frame for a 74-residue protein with 45% identity to CspA. All csp genes were fused in the coding regions with the lacZ gene, and the expression of β-galactosidase was examined for these hybrid genes upon cold shock. A similar cold-shock induction to cspA was observed for cspB but not cspC and cspD. These results Indicate that E. coli has a family of the cspA gene, some of which are induced by cold shock. 相似文献
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The cold-shock response — a hot topic 总被引:4,自引:2,他引:2
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Amanda G. Jeffreys Karla M. Hak Robert J. Steffan John W. Foster Asim K. Bej 《Current microbiology》1998,36(1):29-35
Salmonella enteritidis is a major foodborne microbial pathogen that can grow and survive at low temperatures for a considerable period of time.
Increased survival was evidenced from a frozen S. enteritidis culture when treated at 10°C prior to freezing. Western blot analysis with Escherichia coli CspA antibody and analysis of radiolabeled proteins from S. enteritidis cultures after cold shock at 10°C and 5°C showed increased expression of a 7.4-kDa major cold shock protein, CS7.4, similar
in size to that reported for E. coli. Cloning followed by nucleotide sequence analysis of the cspA gene from S. enteritidis showed a 100% nucleotide sequence identity in the promoter elements (−35 and −10) and the amino acid sequence encoded by
the open reading frame (ORF) with the E. coli cspA gene. However, the differences in the nucleotide sequences between E. coli and S. enteritidis cspA genes in the putative repressor protein binding domain, the fragment 7, and in various segments throughout the upstream 0.642-kbp
DNA may contribute to the expression of CS7.4 at less stringent temperatures in S. enteritidis. As in E. coli, the actual role of CS7.4 in protecting S. enteritidis from the damaging effects of cold or freezing temperatures is not yet understood.
Received: 14 March 1997 / Accepted: 10 July 1997 相似文献
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Takefumi Kofuji Tomonori Fujiwara Masumi Sanada Tatsuya Mishima Kimio Akagawa 《Journal of neurochemistry》2014,130(4):514-525
Two types of syntaxin 1 isoforms, HPC‐1/syntaxin 1A (STX1A) and syntaxin 1B (STX1B), are thought to have similar functions in exocytosis of synaptic vesicles. STX1A?/? mice which we generated previously develop normally, possibly because of compensation by STX1B. We produced STX1B?/? mice using targeted gene disruption and investigated their phenotypes. STX1B?/? mice were born alive, but died before postnatal day 14, unlike STX1A?/? mice. Morphologically, brain development in STX1B?/? mice was impaired. In hippocampal neuronal culture, the cell viability of STX1B?/? neurons was lower than that of WT or STX1A?/? neurons after 9 days. Interestingly, STX1B?/? neurons survived on WT or STX1A?/? glial feeder layers as well as WT neurons. However, STX1B?/? glial feeder layers were less effective at promoting survival of STX1B?/? neurons. Conditioned medium from WT or STX1A?/? glial cells had a similar effect on survival, but that from STX1B?/? did not promote survival. Furthermore, brain‐derived neurotrophic factor (BDNF) or neurotrophin‐3 supported survival of STX1B?/? neurons. BDNF localization in STX1B?/? glial cells was disrupted, and BDNF secretion from STX1B?/? glial cells was impaired. These results suggest that STX1A and STX1B may play distinct roles in supporting neuronal survival by glia.
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Kelly L. Arnett W. Huang Nicholas M. Valiante Linda D. Barber P. Parham 《Immunogenetics》1998,48(1):56-61
HLA-B*0801 is unique among HLA-B allotypes in having dominant amino acid anchors at positions 3 and 5 of the peptide-binding motif.
HLA-B*0802 is a variant of HLA-B*0801 in which the Bw6 sequence motif is replaced by a Bw4 sequence motif. This change, involving substitutions at positions
77, 80, 81, 82, and 83 of the B*08 heavy chain, is probably the result of a single evolutionary event of interallelic conversion. Moreover, the difference
between B*0802 and B*0801 is sufficient to stimulate a cytotoxic T-cell response. To assess further the functional impact of the Bw4 motif on a
B8 background, we compared the peptide-binding specificity of the B*0801 and B*0802 allotypes by sequencing the mixture of peptides endogenously bound to B*0802 and 12 individual peptides purified from that mixture. The HLA-B*0802 allotype, while able to bind some peptides bound by B*0801, has a broader repertoire of endogenously bound peptides than B*0801: the peptides bound by B*0802 are more variable in length and exhibit greater diversity in the carboxyl-terminal amino acid which interacts with the
F pocket.
Received: 29 October 1997 相似文献
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Verbenko V. N. Kuznetsova L. V. Smol'nikova A. V. Kalinin V. L. 《Russian Journal of Genetics》2003,39(6):618-626
Plasmid pCspA::Km carrying a cloned mutant allele of the cspA gene for the major Escherichia coli cold-shock protein CspA with an insertion of the kanamycin resistance gene cassette from transposon Tn903 into the core region of the coding sequence causes a 2.3-fold increase in radioresistance of wild-type E. coli cells (cspA
+). The radiation protective effect of this plasmid is abolished or drastically reduced in mutants recA13and rpoH15defective in RecA protein and in induction of the heat-shock protein regulon, respectively. Plasmid pCspA::Km causes a 1.3-fold elevation in the resistance to -irradiation of E. coli mutants with an intermediate level of radiation resistance (Gamr445 and KS0160) but slightly diminishes resistance of a highly radiation-resistant Gamr444 mutant. In the chromosome of E. coli strain with normal DNA repair systems, the cspA::Km mutation in the homozygous state enhances resistance to the lethal effect of -rays and UV light 2.9 and 1.4 times, respectively. These data suggest that the system of cold-shock proteins can modulate resistance of E. colicells to the lethal effect of -rays and UV light. 相似文献
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Thomas V. Getchell Mary Grillo Suresh S. Tate Reiko Urade John Teeter Dr. Frank L. Margolis 《Neurochemical research》1990,15(4):449-456
We demonstrate that poly (A+)RNA isolated from catfish barbels directs the expression of functional amino acid taste receptors in theXenopus oocyte. The activity of these receptors is monitored in ovo by the two electrode voltage clamp technique. Specific conductance changes recorded in response to amino acid stimulation are analogous to those recorded electrophysiologically from intact catfish barbels. These responses exhibit specificity, reproducibility, rapid onset and termination, and desensitization to repetitive stimulation. A functional assay system that encompasses the full complement of transduction events from the ligand-receptor interaction to subsequent conductance changes is necessary to identify molecular components responsible for these events. Our results demonstrate that theXenopus oocyte can be used to characterize and identify clones coding for amino acid taste receptors analogous to its use in studying receptor molecules for other neuroactive compounds.Special issue is dedicated to Dr. Sidney Udenfriend. 相似文献
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Na+-dependent neutral amino acid transport into the bovine renal epithelial cell line NBL-1 is catalysed by a broad-specificity transporter originally termed System B0. This transporter is shown to differ in specificity from the B0 transporter cloned from JAR cells [J. Biol. Chem. 271 (1996) 18657] in that it interacts much more strongly with phenylalanine. Using probes designed to conserved transmembrane regions of the ASC/B0 transporter family we have isolated a cDNA encoding the NBL-1 cell System B0 transporter. When expressed in Xenopus oocytes the clone catalysed Na+-dependent alanine uptake which was inhibited by glutamine, leucine and phenylalanine. However, the clone did not catalyse Na+-dependent phenylalanine transport, again as in NBL-1 cells. The clone encoded a protein of 539 amino acids; the predicted transmembrane domains were almost identical in sequence to those of the other members of the B0/ASC transporter family. Comparison of the sequences of NBL-1 and JAR cell transporters showed some differences near the N-terminus, C-terminus and in the loop between helices 3 and 4. The NBL-1 B0 transporter is not the same as the renal brush border membrane transporter since it does not transport phenylalanine. Differences in specificity in this protein family arise from relatively small differences in amino acid sequence. 相似文献