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J Pidoux

Publications and source records attributed to J Pidoux.

6 recordsLinked to original sources
PubMed2000

Alternative splicing in the human interleukin enhancer binding factor 3 (ILF3) gene.

The Interleukin Enhancer Binding Factor 3 (ILF3) gene has been mapped to chromosome 19 in humans and to chromosome 9 in mice. Several reported double-stranded RNA binding proteins including NF90, ILF3, MPP4 and DRBP76 have been suggested to be isoforms of the ILF3 gene but this has not been clearly established. We isolated several ilf3 transcripts from a melanoma cDNA library and two corresponding genomic fragments, and report alternative splicing and polyadenylation site selection in the human ILF3 gene. We show the existence of an alternative splice site responsible for the sequence divergence in the 3' part of the transcripts. Another alternative splicing event at a site between the two double-stranded RNA binding motifs leads to the additional presence in some cases of a four amino acids NVKQ peptide. We also describe the utilization of three distinct polyadenylation signals and the generation of an ilf3 transcript with a long extended 3' UTR. The expression of the different transcripts was evaluated. We used a GenBank sequence for the part of chromosome 19 corresponding to the ILF3 gene to determine the exon-intron organization of the entire gene which spans 38 kb and is divided into 21 exons.

Alternative Splicing↗
PubMed1998

A bacterial two-hybrid system based on a reconstituted signal transduction pathway.

We describe a bacterial two-hybrid system that allows an easy in vivo screening and selection of functional interactions between two proteins. This genetic test is based on the reconstitution, in an Escherichia coli cya strain, of a signal transduction pathway that takes advantage of the positive control exerted by cAMP. Two putative interacting proteins are genetically fused to two complementary fragments, T25 and T18, that constitute the catalytic domain of Bordetella pertussis adenylate cyclase. Association of the two-hybrid proteins results in functional complementation between T25 and T18 fragments and leads to cAMP synthesis. Cyclic AMP then triggers transcriptional activation of catabolic operons, such as lactose or maltose, that yield a characteristic phenotype. In this genetic test, the involvement of a signaling cascade offers the unique property that association between the hybrid proteins can be spatially separated from the transcriptional activation readout. This permits a versatile design of screening procedures either for ligands that bind to a given "bait," as in the classical yeast two-hybrid system, or for molecules or mutations that block a given interaction between two proteins of interest.

Adenylyl Cyclases↗
PubMed1998

Pleiotropic effects of cAMP on germination, antibiotic biosynthesis and morphological development in Streptomyces coelicolor.

In wild-type Streptomyces coelicolor MT1110 cultures, cyclic adenosine 3',5' monophosphate (cAMP) was synthesized throughout the developmental programme with peaks of accumulation both during germination and later when aerial mycelium and actinorhodin were being produced. Construction and characterization of an adenylate cyclase disruption mutant (BZ1) demonstrated that cAMP facilitated these developmental processes. Although pulse-labelling experiments showed that a similar germination process was initiated in BZ1 and MT1110, germ-tube emergence was severely delayed in BZ1 and never occurred in more than 85% of the spores. Studies of growth and development on solid glucose minimal medium (SMMS, buffered or unbuffered) showed that MT1110 and BZ1 produced acid during the first rapid growth phase, which generated substrate mycelium. Thereafter, on unbuffered SMMS, only MT1110 resumed growth and produced aerial mycelium by switching to an alternative metabolism that neutralized its medium, probably by reincorporating and metabolizing extracellular acids. BZ1 was not able to neutralize its medium or produce aerial mycelium on unbuffered SMMS; these defects were suppressed by high concentrations (>1 mM) of cAMP during early growth or on buffered medium. Other developmental mutants (bldA, bldB, bldC, bldD, bldG) also irreversibly acidified this medium. However, these bald mutants were not suppressed by exogenous cAMP or neutralizing buffer. BZ1 also differentiated when it was cultured in close proximity to MT1110, a property observed in cross-feeding experiments between bald mutants and commonly thought to reflect diffusion of a discrete positively acting signalling molecule. In this case, MT1110 generated a more neutral pH environment that allowed BZ1 to reinitiate growth and form aerial mycelium. The fact that actinorhodin synthesis could be induced by concentrations of cAMP (< 20 microM) found in the medium of MT1110 cultures, suggested that it may serve as a diffusible signalling molecule to co-ordinate antibiotic biosynthesis.

Adenylyl Cyclases↗
PubMed1993

The adenylate cyclase catalytic domain of Streptomyces coelicolor is carboxy-terminal.

A DNA fragment of Streptomyces coelicolor encoding the carboxy-terminal catalytic domain of adenylate cyclase was cloned, sequenced and expressed in an Escherichia coli cya-defective strain where it produced nanomole levels of cAMP. The amino acid sequence of the enzyme displays similarities with the Brevibacterium liquefaciens pyruvate regulated adenylate cyclase.

Adenylyl Cyclases↗
PubMedDate not supplied

An Escherichia coli insertion element (IS2) provides a functional promoter in Bordetella pertussis.

The adenylate cyclase (cyaA) gene of Bordetella pertussis is not expressed in Escherichia coli. Using cya-lac fusions, high-expression spontaneous mutants were isolated and shown to have the insertion element IS2 in orientation II integrated into the reading frame of cyaA. Upon transfer of the IS2-activated cya-lac fusion into B. pertussis, we found that the IS2-provided promoter is as efficient in B. pertussis as it is in E. coli. These results provide evidence that an insertion element derived from the E. coli chromosome can activate gene expression in B. pertussis, a taxonomically distant organism.

Adenylyl Cyclases↗