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Bp Downstream (bp + downstream)
Selected AbstractsRegulation of anaerobic arginine catabolism in Bacillus licheniformis by a protein of the Crp/Fnr familyFEMS MICROBIOLOGY LETTERS, Issue 2 2000Abdelouahid Maghnouj Abstract Arginine anaerobic catabolism occurs in Bacillus licheniformis through the arginine deiminase pathway, encoded by the gene cluster arcABDC. We report here the involvement of a new protein, ArcR, in the regulation of the pathway. ArcR is a protein of the Crp/Fnr family encoded by a gene located 109 bp downstream from arcC. It binds to a palindromic sequence, very similar to an Escherichia coli Crp binding site, located upstream from arcA. Residues in the C-terminal domain of Crp that form the DNA binding motif, in particular residues Arg-180 and Glu-181 that make specific bonds with DNA, are conserved in ArcR, suggesting that the complexes formed with DNA by Crp and ArcR are similar. Moreover, the pattern of DNase I hypersensitivity sites induced by the binding of ArcR suggests that ArcR bends the DNA in the same way as Crp. From the absence of anaerobic induction following inactivation of arcR and from the existence of a binding site upstream of the arcA transcription start point, it can be inferred that ArcR is an activator of the arginine deiminase pathway. [source] MLL/GRAF fusion in an infant acute monocytic leukemia (AML M5b) with a cytogenetically cryptic ins(5;11)(q31;q23q23)GENES, CHROMOSOMES AND CANCER, Issue 4 2004Ioannis Panagopoulos More than 30 fusions involving the MLL gene at 11q23 have been reported in acute myeloid leukemia (AML). Some of these chimeras are rather common, such as MLL/MLLT3(AF9), but many are quite rare, with some, for example, MLL/GRAF, described only in a single case. The MLL/GRAF fusion, in which the reciprocal hybrid was not expressed, suggesting that the former transcript was the leukemogenic one, was detected in a juvenile myelomonocytic leukemia with a t(5;11)(q31;q23). Here, we report a second case,an infant acute monocytic leukemia (AML M5b),with an MLL/GRAF fusion. By conventional G-banding, the karyotype was normal. However, Southern blot and fluorescence in situ hybridization analyses revealed that MLL was rearranged and that the 5, part of the MLL gene was inserted into 5q in the vicinity of 5q31, which harbors GRAF. Reverse-transcriptase polymerase chain reaction (PCR) showed that exon 9 of MLL was fused in-frame with exon 19 of GRAF. Extralong genomic PCR with subsequent sequence analysis demonstrated that the breakpoints occurred in intron 9 of MLL, nine base pairs (bp) downstream from exon 9, and in intron 18 of GRAF, 117 bp downstream from exon 18. A 6-bp insertion (ACACTC) of unknown origin was present at the junction. The putative MLL/GRAF fusion protein would retain the AT-hook DNA-binding domain, the DNA methyl transferase motif, the transcription repression domain of MLL, and the SH3 domain of GRAF. As expected, the reciprocal GRAF/MLL was neither expressed nor generated at the genomic level as a consequence of the ins(5;11)(q31;q23q23). On the basis of the now-reported two cases with MLL/GRAF, we conclude that this transcript,but not the reciprocal one,characterizes a rare genetic subgroup of infant AML. © 2004 Wiley-Liss, Inc. [source] Non-muscle myosin heavy chain (MYH9): A new partner fused to ALK in anaplastic large cell lymphomaGENES, CHROMOSOMES AND CANCER, Issue 4 2003Laurence Lamant In anaplastic large cell lymphoma, the ALK gene at 2p23 is known to be fused to NPM, TPM3, TPM4, TFG, ATIC, CLTC, MSN, and ALO17. All of these translocations result in the expression of chimeric ALK transcripts that are translated into fusion proteins with tyrosine kinase activity and oncogenic properties. We report a case showing a restricted cytoplasmic staining pattern of ALK and a novel chromosomal abnormality, t(2;22)(p23;q11.2), demonstrated by fluorescence in situ hybridization analysis. The result of 5, RACE analysis showed that the ALK gene was fused in-frame to a portion of the non-muscle myosin heavy chain gene, MYH9. Nucleotide sequence of the MYH9-ALK chimeric cDNA revealed that the ALK breakpoint was different from all those previously reported. It is localized in the same exonic sequence as MSN-ALK, but 6 bp downstream, resulting in an in-frame fusion of the two partner proteins. In contrast to the previously reported ALK fusion proteins, MYH9-ALK may lack a functional oligomerization domain. However, biochemical analysis showed that the new fusion protein is tyrosine phosphorylated in vivo but seems to lack tyrosine kinase activity in vitro. If further investigations confirm this latter result, the in vivo tyrosine phosphorylation of MYH9-ALK protein could involve mechanisms different from those described in the other ALK hybrid proteins. © 2003 Wiley-Liss, Inc. [source] The expression of recombinant genes in Escherichia coli can be strongly stimulated at the transcript production level by mutating the DNA-region corresponding to the 5,-untranslated part of mRNAMICROBIAL BIOTECHNOLOGY, Issue 3 2009Laila Berg Summary Secondary structures and the short Shine,Dalgarno sequence in the 5,-untranslated region of bacterial mRNAs (UTR) are known to affect gene expression at the level of translation. Here we report the use of random combinatorial DNA sequence libraries to study UTR function, applying the strong, ,32/,38 -dependent, and positively regulated Pm promoter as a model. All mutations in the libraries are located at least 8 bp downstream of the transcriptional start site. The libraries were screened using the ampicillin-resistance gene (bla) as reporter, allowing easy identification of UTR mutants that display high levels of expression (up to 20-fold increase relative to the wild-type at the protein level). Studies of the two UTR mutants identified by a modified screening procedure showed that their expression is stimulated to a similar extent at both the transcript and protein product levels. For one such mutant a model analysis of the transcription kinetics showed significant evidence of a difference in the transcription rate (about 18-fold higher than the wild type), while there was no evidence of a difference in transcript stability. The two UTR sequences also stimulated expression from a constitutive ,70 -dependent promoter (P1/Panti-tet), demonstrating that the UTR at the DNA or RNA level has a hitherto unrecognized role in transcription. [source] | ||||||||||