Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The possible interaction of the trans-acting mobilization proteins, MobL and MobS, at the cognate origin of transfer (oriT) region of the Thiobacillus ferrooxidans plasmid pTF1 has been investigated. In gel retardation assays with crude protein extracts from overproducing strains, a truncated MobL (c. 28 kDa) as well as its native protein (42 kDa), but not the 11 kDa MobS protein, were found to bind specifically to a 42-mer oligonucleotide which represents the transferred DNA strand of the minimal oriT fragment of pTF1. In vivo, the binding of MobL was studied by monitoring catechol 2,3-dioxygenase (xylE) activities driven by promoters of the divergently transcribed mobL and mobS genes. The mob promoter sequences were found to resemble the Escherichia coli sigma 70-dependent consensus promoter elements. The '-10' recognition sequences of mobL and one of the two mobS promoters overlap except for one base and they are positioned within the putative 'hairpin' structure in the minimal oriT sequence. In accordance with the twin supercoil-domain model of Liu and Wang (1987) which suggests that transcription can generate local variations in DNA superhelicity, we propose a possible physiological role of DNA supercoiling in the transfer origin with reference to divergent transcription of mobL and mobS genes.
Mol Microbiol 1992 Apr
PMID:Mobilization protein-DNA binding and divergent transcription at the transfer origin of the Thiobacillus ferrooxidans pTF1 plasmid. 158 23

Helicases are essential to both DNA replication and transcription because they separate double-stranded DNA, preparing the single strands for replication or transcription. Because the anti-cancer anthracycline antibiotics stabilize double-stranded DNA primarily by their intercalative binding, we expected the intercalated antibiotics to interfere with helicase action. We examined anthracycline antibiotic effects on SV40 large T antigen helicase activity, using a duplex DNA helicase substrate of 32P-labeled 17-mer annealed to complementary M13mp19(+) circular single-stranded DNA. The T antigen helicase activity was potently inhibited by the anthracycline antibiotics. The T antigen helicase IC50 values for the anthracycline antibiotics were as follows: nogalamycin, 2 x 10(-7) M; daunorubicin, 4 x 10(-7) M; doxorubicin, 4 x 10(-7) M; idarubicin, 1.8 x 10(-6) M; 4'-epidoxorubicin, 2 x 10(-6) M; aclacinomycin, 4 x 10(-6) M; and menogaril, 6 x 10(-6) M. Partially purified helicases from HeLa cells and murine mammary carcinoma FM3A cells also were potently inhibited by doxorubicin, with IC50 values of 4 x 10(-7) M and 9 x 10(-7) M, respectively. Because the abundance, specificities, and types of helicases vary in the cell, this site of action for anthracycline antibiotics may help explain anthracycline potency, drug specificity for DNA or RNA inhibition, and some types of cellular resistance to these drugs.
Mol Pharmacol 1992 Jun
PMID:Helicase inhibition by anthracycline anticancer agents. 161 15

Sequence-specific spin-labeled oligodeoxynucleotides with conformation-sensitive electron paramagnetic resonance (EPR) signals are synthesized and examined as solution-phase nucleic acid hybridization probes. Either a proxyl or tempo ring linked to the C(5) position of deoxyuridine (dU) by a nonrigid two-atom methylamino tether is incorporated within 15-mers by phosphotriester chemistry yielding stable spin-labeled probes with distinctive EPR specific activity (AEPR) values. The AEPR is greater for a proxyl-labeled than for a tempo-labeled probe and is consistent with EPR data of enzymatically labeled 26-mers [Bobst, A. M., Pauly, G. T., Keyes, R. S., and Bobst, E. V. (1988) FEBS Lett. 228, 33-36], after normalizing for percent labeling. The spectral characteristics of the free probes and the probe/target complexes are similar to those of enzymatically spin-labeled nucleic acids containing a different nonrigid two-atom-tethered spin label [Bobst, A. M., Kao, S.-C., Toppin, R. C., Ireland, J. C., and Thomas, I. E. (1984) J. Mol. Biol. 173, 63-70]. The presence of target DNA is detected in solution by EPR spectroscopy and the assay is based on the characteristic line-shape change associated with hybridization. The EPR spectra of free and bound probe reflect little interference from changes in global dynamics of the probe, and the line-shape change upon complexation results primarily from a change in local base dynamics. The presence or absence of hybridization can be detected in a loop-gap resonator with about 1 pmol of spin-labeled 15-mer within minutes.
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PMID:Preparation and characterization of spin-labeled oligonucleotides for DNA hybridization. 165 Nov 16

In vitro transcripts from the 3' flanking regions of mustard chloroplast genes were tested for protein binding in a chloroplast extract. Efficient and sequence-specific RNA-protein interaction was detected with transcripts of the genes trnK, rps16 and trnH, but not with the 3' terminal region of trnQ RNA. The transacting component required for specific complex formation is probably a single 54 kDa polypeptide. The protein-binding region of the rps16 3' terminal region was mapped and compared with that of the trnK transcript determined previously. Both regions reveal a conserved 7-mer UUUAUCU followed by a stretch of U residues. Deletion of the trnK 3' U cluster resulted in more than 80% reduction in the binding activity, and after deletion of both the U stretch and the 7-mer motif no binding at all was detectable. RNase protection experiments indicate that the protein-binding regions of both the rps16 and trnK transcripts correlate with the positions of in vivo 3' ends, suggesting an essential role for the 54 kDa binding protein in RNA 3' end formation. In the case of the trnK gene, evidence was obtained for read-through transcripts that extend into the psbA coding region, thus pointing to the possibility of trnK-psbA cotranscription.
Mol Gen Genet 1991 Aug
PMID:RNA-protein interactions at transcript 3' ends and evidence for trnK-psbA cotranscription in mustard chloroplasts. 171 78

Using a 17-mer synthetic peptide for immunization, a polyclonal antibody (WS933) directed against amino acid residues 395-411 of the mouse glucocorticoid receptor (GCR) has been raised and used to probe the significance of this region in forming the receptor oligomer and to localize the truncation site of the mutant GCR of the P1798 lymphosarcoma. This region of the receptor, which encompasses the BUGR epitope, is amino-terminal of and immediately adjacent to the DNA-binding domain. The polyclonal antibody WS933 reacted with both native and denatured forms of the wild-type mouse GCR as judged by its ability to shift the transformed receptor peak on Sephacryl S300 columns, to immunoadsorb the receptor to protein A Sepharose, and by immunoblot analysis where it identified the 98 kDa receptor protein in the cortisol-sensitive line of the P1798 mouse lymphosarcoma. WS933 also reacted with rat and rabbit GCR, but not human GCR. These characteristics were shared by the BUGR-2 monoclonal antibody. Unexpectedly, there were two highly significant differences between WS933 and BUGR-2. The first was the ability of WS933 to bind to the mutant 45 kDa GCR of the cortisol-resistant P1798 lymphosarcoma as judged by its capability of shifting the receptor peak on Sephacryl S300 columns. BUGR-2, in contrast, was unable to shift this mutant receptor peak. Secondly, WS933 was unable to react with the non-DNA-binding form of the wild-type (or mutant) GCR, whereas BUGR-2 could react with the non-DNA-binding form of the wild-type GCR. The first observation suggests that the truncation site of the mutant receptor may lie within a portion of the BUGR domain. Additionally, the second observation implies that at least part of the region lying within amino acid residues 395-411 of the mouse GCR is occluded in the receptor oligomer and that this site only becomes available upon transformation of the GCR to the DNA-binding form. This data provides the first mapping of the amino-terminus of the occluded region of the non-transformed receptor, and suggests that WS933 will be a useful probe for characterizing mutant as well as wild type glucocorticoid receptors.
J Steroid Biochem Mol Biol 1991 Oct
PMID:New site-directed polyclonal antibody maps N-terminus of occluded region of the non-transformed glucocorticoid receptor oligomer to within BUGR epitope. 171 70

A new member of a family of site-specific retrotransposons is described in the New World trypanosome Trypanosoma cruzi. This element, CZAR (cruzi-associated retrotransposon), resembles two previously described retrotransposons found in the African trypanosome T. brucei gambiense and the mosquito trypanosomatid Crithidia fasciculata in specifically inserting between nucleotides 11 and 12 of the highly conserved 39-mer of the spliced leader RNA (SL-RNA) gene. CZAR is similar in overall organization to the other two SL-RNA-associated elements. It possesses two potential long open reading frames which resemble the gag and pol genes of retroviruses. In the pol open reading frame, all three elements contain similarly arranged endonuclease domains and share extensive amino acid homology in the reverse transcriptase region. All are associated with the SL-RNA gene locus and are present in low copy numbers. They do not appear to have 5' truncated versions. All three retrotransposons are otherwise quite distinct from one another, with no significant overall amino acid homology. The presence of such retroelements inserted into the identical site within SL-RNA gene sequences in at least three evolutionarily distant trypanosomatid species argues for a functional role. Because these elements appear to have a precise target site requirement for integration, we refer to them as SL siteposons.
Mol Cell Biol 1991 Dec
PMID:A new member of a family of site-specific retrotransposons is present in the spliced leader RNA genes of Trypanosoma cruzi. 171 80

Within the replication origin, oriC, of the Escherichia coli chromosome, novel in vivo transcripts were detected which proceeded rightward and whose production was activated by DnaA protein. In contrast, DnaA protein repressed the previously described ori-L leftward transcription. The former should introduce negative supercoiling, and the latter positive supercoiling, into the 13-mers. The effects of transcription on the initiation of replication were also investigated by making constructs with promoters placed near oriC. Transcription was found to enhance the origin activity only when it was oriented in such a way as to introduce negative supercoiling into the 13-mers. From these results, we propose that transcription within oriC regulates replication initiation by altering the topology of the 13-mer region.
Mol Gen Genet 1992 Jan
PMID:Transcription in vivo within the replication origin of the Escherichia coli chromosome: a mechanism for activating initiation of replication. 173 90

Five human PRL-secreting pituitary tumors were tested for the presence of DNA-transforming sequences. After calcium phosphate transfection to NIH-3T3 mouse fibroblast cells, DNA samples derived from two prolactinomas induced foci of morphologically transformed cells which subsequently grew in soft agar. After retransfection of transformant DNA, resulting secondary transformants elicited rapidly growing solid tumors in nude mice. Southern analysis of transformant DNA revealed the integration of Alu-positive human DNA sequences into the mouse fibroblast NIH-3T3 cells, as judged by hybridization to a Blur-8 probe. The Alu signal became increasingly more difficult to detect with the multiple passaging (greater than 20) of transformant cells in culture. Alu polymerase chain reaction (PCR) was, therefore, used to selectively amplify human DNA sequences from the NIH-3T3 rodent background. PCR using a human Alu-specific primer resulted in amplification of an Alu-containing DNA region within these transformants. The transformant DNA did not hybridize to human genomic probes for genes known to evoke focus formation in this assay, including H-ras, K-ras, N-ras, trk, ret, ros, or met. Further identification of the Alu-containing region revealed that it contained sequences from the human hst gene, a member of the fibroblast growth factor family. The presence of human hst was demonstrated by strong hybridization to a 40-mer oligonucleotide probe to the second exon of hst, by amplification of this region with human hst-nested amplimers within the first and second introns, and finally by direct sequencing.(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Endocrinol 1991 Nov
PMID:Transforming DNA sequences present in human prolactin-secreting pituitary tumors. 177 71

In this work we present the localization and characterization of the repl promoter (Prepl) and show aspects of the regulation. Comparison of Prepl with other autoregulated replication protein gene promoters revealed similarities, but Prepl differs from some of these characterized promoters in not being regulated by the heat-shock RNA polymerase. Primer extension analysis showed that Prepl is contained within five helically aligned 18 base pair repeats, or 18-mers of the previously defined minimal origin. In addition, we find that Prepl is autoregulated by a trans-acting product encoded in the REPI region. Purified Repl protein binds to the 18-mer region of the origin, suggesting that the repl gene is autoregulated by the protein product. The autoregulation appears to be co-operative since decreasing the 18-mer binding site region results in a concomitant non-linear loss of autorepression. The deletion derivatives show a decreased ability to bind the Repl protein when compared with origin DNA containing all of the binding region. The diminished capacity of the various deletion derivatives to bind Repl in vitro correlates with the loss of autorepression seen in vivo.
Mol Microbiol 1991 Dec
PMID:Co-operative autoregulation of a replication protein gene. 180 40

Transcriptional regulation of the gene encoding the amyloid precursor protein (APP) may play an important role in the formation of the amyloid depositions observed in Alzheimer disease and Down syndrome patients. To determine the promoter sequence requirements for the expression of the APP gene, we constructed plasmids containing different parts of the APP gene promoter fused to the bacterial chloramphenicol acetyl transferase (CAT) gene. Transfection of these constructs into Hela and PC12 cells revealed the presence of two blocks of regulatory sequences in the APP promoter. One block extending from about -600 to -460 bp acts as a positive regulator as its removal results in a substantial decrease in promoter activity. A second block of sequences extending from -450 to -150 bp acts like a negative regulator. We have also observed that a 38 mer synthetic oligonucleotide encompassing the region -489 to -452 of the APP promoter stimulated the activity of the heterologous TK promoter, suggesting that this region may be part of an enhancer-like element. In addition, our results suggest that the effects of various APP promoter domains on its activity may be cell specific.
Brain Res Mol Brain Res 1991 Feb
PMID:The promoter activity of the gene encoding Alzheimer beta-amyloid precursor protein (APP) is regulated by two blocks of upstream sequences. 185 27


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