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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We asked whether the antiangiogenic action of 16K human PRL (hPRL), in addition to blocking mitogen-induced vascular endothelial cell proliferation, involved activation of programmed cell death. Treatment with recombinant 16K hPRL increased DNA fragmentation in cultured bovine brain capillary endothelial (BBE) and human umbilical vein endothelial (HUVE) cells in a time- and dose-dependent fashion, independent of the serum concentration. The activation of apoptosis by 16K hPRL was specific for endothelial cells, and the activity of the peptide could be inhibited by heat denaturation, trypsin digestion, and immunoneutralization, but not by treatment with the endotoxin blocker, polymyxin-B. 16K hPRL-induced apoptosis was correlated with the rapid activation of caspases 1 and 3 and was blocked by pharmacological inhibition of caspase activity. Caspase activation was followed by inactivation of two caspase substrates, poly(ADP-ribose) polymerase (PARP) and the inhibitor of caspase-activated deoxyribonuclease (DNase) (ICAD). Furthermore, 16K hPRL increased the conversion of Bcl-X to its proapoptotic form, suggesting that the Bcl-2 protein family may also be involved in 16K hPRL-induced apoptosis. These findings support the hypothesis that the antiangiogenic action of 16K hPRL includes the activation of programmed cell death of vascular endothelial cells.
Mol Endocrinol 2000 Oct
PMID:The antiangiogenic factor 16K PRL induces programmed cell death in endothelial cells by caspase activation. 1104 70

pSAM2 is an 11 kb integrative element from Streptomyces ambofaciens that is capable of conjugal transfer. A system based on differential DNA modification by SalI methyltransferase was used to localize pSAM2 in the donor or recipient strain, and thus to determine the various steps associated with transfer. Initiation (i.e. excision and replication of pSAM2 in the donor) occurs a few hours after mating with a recipient strain. pSAM2 replicates in the recipient strain, spreads within the mycelium and then integrates into the chromosome. Transfer generally involves single-stranded DNA. In Streptomyces, only a few genes, such as traSA for pSAM2, are required for conjugal transfer. Using the differential sensitivity to the SalI restriction-modification system of transfers involving single- and double-stranded DNA, we found that pSAM2 was probably transferred to the recipient as double-stranded DNA. This provides the first experimental evidence for the transfer of double-stranded DNA during bacterial conjugation. Thus, TraSA, involved in pSAM2 transfer, and SpoIIIE, which is involved in chromosome partitioning in Bacillus subtilis, display similarities in both sequence and function: both seem to transport double-stranded DNA actively, either from donor to recipient or from mother cell to prespore.
Mol Microbiol 2001 Oct
PMID:The integrative element pSAM2 from Streptomyces: kinetics and mode of conjugal transfer. 1167 75

The glucocorticoid receptor (GR) is a ligand-activated transcription factor that induces expression of many genes. The GR has been useful for understanding how chromatin structure regulates steroid-induced transcription in model systems. However, the effect of glucocorticoids on chromatin structure has been examined on few endogenous mammalian promoters. We investigated the effect of glucocorticoids on the in vivo chromatin structure of the glucocorticoid-responsive I kappa B alpha gene promoter, the inhibitor of the ubiquitous transcription factor, nuclear factor kappa B (NF kappa B). Glucocorticoids inhibit NF kappa B activity in some tissues by elevating the levels of I kappa B alpha. We found that glucocorticoids activated the I kappa B alpha promoter in human T47D/A1-2 cells containing the GR. We then investigated the chromatin structure of the I kappa B alpha promoter in the absence and presence of glucocorticoids with the use of micrococcal nuclease, restriction enzyme, and deoxyribonuclease (DNaseI) analyses. In untreated cells, the promoter assembles into regularly positioned nucleosomes, and glucocorticoid treatment did not alter nucleosomal position. Restriction enzyme accessiblity studies indicated that the I kappa B alpha promoter is assembled as phased nucleosomes that adopt an "open" chromatin architecture in the absence of hormone. However, glucocorticoids may be required for transcription factor binding, because DNaseI footprinting studies suggested that regulatory factors bind to the promoter upon glucocorticoid treatment.
Mol Biol Cell 2001 Nov
PMID:Glucocorticoid receptor activation of the I kappa B alpha promoter within chromatin. 1169 73

Helicobacter pylori, Gram-negative, curved bacteria colonizing the human stomach, possess strain-specific complements of functional restriction-modification (R-M) systems. Restriction-modification systems have been identified in most bacterial species studied and are believed to have evolved to protect the host genome from invasion by foreign DNA. The large number of R-Ms homologous to those in other bacterial species and their strain-specificity suggest that H. pylori may have horizontally acquired these genes. A type IIs restriction-modification system, hpyIIRM, was active in two out of the six H. pylori strains studied. We demonstrate now that in most strains lacking M.HpyII function, there is complete absence of the R-M system. Direct DNA repeats of 80 bp flanking the hpyIIRM system allow its deletion, resulting in an "empty-site" genotype. We show that strains possessing this empty-site genotype and strains with a full but inactive hpyIIRM can reacquire the hpyIIRM cassette and functional activity through natural transformation by DNA from the parental R-M+ strain. Identical isolates divergent for the presence of an active HpyII R-M pose different restriction barriers to transformation by foreign DNA. That H. pylori can lose HpyII R-M function through deletion or mutation, and can horizontally reacquire the hpyIIRM cassette, is, in composite, a novel mechanism for R-M regulation, supporting the general hypothesis that H. pylori populations use mutation and transformation to regulate gene function.
Mol Microbiol 2001 Oct
PMID:Regulation of the HpyII restriction-modification system of Helicobacter pylori by gene deletion and horizontal reconstitution. 1170 61

The BstF5I restriction-modification system from Bacillus stearothermophilus F5, unlike all known restriction-modification systems, contains three genes encoding DNA methyltransferases. In addition to revealing two DNA methylases responsible for modification of adenine in different DNA strands, it has been first shown that one bacterial cell has two DNA methylases, M.BstF5I-1 and M.BstF5I-3, with similar substrate specificity. The boundaries of the gene for DNA methyltransferase M.BstF5I-1 have been verified. The bstF5IM-1 gene was cloned in pJW and expressed in Escherichia coli. Homogeneous samples of M.BstF5I-1 and M.BstF5I-3 were obtained by chromatography with different sorbents. The main kinetic parameters have been determined for M.BstF5I-1 and M.BstF5I-3, both modifying adenine in the recognition site 5'-GGATG-3'.
Mol Biol (Mosk)
PMID:[Comparative study of the M.Bstf5I-1 and M.BstF5I-3 DNA methyltransferases from the Bacillus stearothermophilus F5 restriction-modification system]. 1186 4

The primary structures of the plasmids pECL18 (5571 bp) and pKPN2 (4196 bp) from Escherichia coli and Klebsiella pneumoniae, respectively, which carry genes for a Type II restriction-modification system (RMS2) with the specificity 5'-CCNGG-3', were determined in order to elucidate the structural relationship between them. The data suggest a possible role for recombination events at bom (basis of mobility) regions and the sites of resolution of multimer plasmid forms (so-called cer sequences) in the structural evolution of multicopy plasmids. Analysis of the sequences of pECL18 and pKPN2 showed that the genes for RM* Ecl18kI and RM* Kpn2kI, and the sequences of the rep (replication) regions in the two plasmids, are almost identical. In both plasmids, these regions are localized between the bom regions and the cer sites. The rest of the pECL18 sequence is almost identical to that of the mob (mobilization) region of ColE1, and the corresponding segment of pKPN2 is almost identical to part of pHS-2 from Shigella flexneri. The difference in primary structures results in different mobilization properties of pECL18 and pKPN2. The complete sequences of pECL18, pKPN2 and the pairwise comparison of the sequences of pECL18, pKPN2, ColE1 and pHS-2 suggest that plasmids may exchange DNA units via site-specific recombination events at bom and cer sites. In the course of BLASTN database searches using the cer sites of pECL18 and pKPN2 as queries, we found twenty cer sites of natural plasmids. Alignment of these sequences reveals that they fall into two classes. The plasmids in each group possess related segments between their cer and bom sites.
Mol Genet Genomics 2002 Apr
PMID:Characterization of pECL18 and pKPN2: a proposed pathway for the evolution of two plasmids that carry identical genes for a Type II restriction-modification system. 1197 60

A fragment containing the SfeI restriction-modification system (RMS) operon was cloned from a Streptococcus faecalis SE72 plasmid. Nucleotide sequence analysis revealed its high (99.2%) homology to the operon for Lactococcus lactis subsp. cremoris W56 LlaBI RMS recognizing the same site, 5'-CTRYAG-3'. A substantial difference was that SfeI RMS operon had an additional 198-bp fragment and a larger gene for the putative control protein. No homology was observed between operon-flanking sequences of the two closely related species, suggesting horizontal transfer of the operon.
Mol Biol (Mosk)
PMID:[Comparison of the homologous SfeI and LlaBI restriction-modification systems]. 1206 27

The Escherichia coli dam adenine-N6 methyltransferase modifies DNA at GATC sequences. It is involved in post-replicative mismatch repair, control of DNA replication and gene regulation. We show that E. coli dam acts as a functional monomer and methylates only one strand of the DNA in each binding event. The preferred way of ternary complex assembly is that the enzyme first binds to DNA and then to S-adenosylmethionine. The enzyme methylates an oligonucleotide containing two dam sites and a 879 bp PCR product with four sites in a fully processive reaction. On lambda-DNA comprising 48,502 bp and 116 dam sites, E. coli dam scans 3000 dam sites per binding event in a random walk, that on average leads to a processive methylation of 55 sites. Processive methylation of DNA considerably accelerates DNA methylation. The highly processive mechanism of E. coli dam could explain why small amounts of E. coli dam are able to maintain the methylation state of dam sites during DNA replication. Furthermore, our data support the general rule that solitary DNA methyltransferase modify DNA processively whereas methyltransferases belonging to a restriction-modification system show a distributive mechanism, because processive methylation of DNA would interfere with the biological function of restriction-modification systems.
J Mol Biol 2002 Jun 21
PMID:The Escherichia coli dam DNA methyltransferase modifies DNA in a highly processive reaction. 1207 49

Contamination of polymerase chain reaction (PCR) reagents continues to be a major problem when consensus primers are used for detection of low concentrations of bacterial DNA. We designed a real-time polymerase chain reaction (PCR) for quantification of bacterial DNA by using consensus primers that bind specifically to the 16S region of bacterial DNA. We have tested four different methods of decontamination of PCR reagents in a project aimed at detecting bacterial DNA at low concentrations: deoxyribonuclease (DNAse) treatment, restriction endonuclease digestion, UV irradiation, and 8-methoxypsoralen in combination with long-wave UV light to intercalate contaminating DNA into double-stranded DNA. All four methods result in inhibition of the PCR reaction, and most of the decontamination procedures failed to eliminate the contaminating bacterial DNA. Only the DNAse decontamination proved to be efficient in eliminating contaminating DNA while conserving PCR efficiency. All four decontamination methods are time consuming and have the possibility of carrying new contamination into the reaction mixture. However, decontamination with DNAse may help, together with the use of highly purified PCR reagents, in detecting small amounts of bacterial DNA in clinical specimens.
Mol Biotechnol 2002 Nov
PMID:Comparison of different decontamination methods for reagents to detect low concentrations of bacterial 16S DNA by real-time-PCR. 1244 78

The nucleotide sequence was established for the full-length Flavobacterium aquatile operon coding for the FauI restriction-modification system. The operon is unusual in structure and has the gene order control protein gene-DNA methyltransferase A gene-restriction endonuclease gene-DNA methyltransferase B gene, other than in the known analogs. The genes are similarly oriented and overlap. On evidence of sequence analysis, both methyltransferases are C5 enzymes, the control protein is similar to that of other restriction-modification systems, and restriction endonuclease is low-homologous to other enzymes cleaving the DNA upper strand in position 4 or 5 relative to the recognition site.
Mol Biol (Mosk)
PMID:[The unique FauI restriction-modification system: cloning and comparative analysis of protein structure]. 1294 34


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