General transcription factor from Escherichia coli with a distinct mechanism of action.

Gene expression in Escherichia coli is controlled by well-established mechanisms that activate or repress transcription. Here, we identify CedA as an unconventional transcription factor specifically associated with the RNA polymerase (RNAP) σ70 holoenzyme. Structural and biochemical analysis of CedA bound to RNAP reveal that it bridges distant domains of ß and σ70 subunits to stabilize an open-promoter complex. CedA does so without contacting DNA. We further show that cedA is strongly induced in response to amino acid starvation, oxidative stress and aminoglycosides. CedA provides a basal level of tolerance to these clinically relevant antibiotics, as well as to rifampicin and peroxide. Finally, we show that CedA modulates transcription of hundreds of bacterial genes, which explains its pleotropic effect on cell physiology and pathogenesis.

Análise do gene PROP1 em pacientes com hipopituitarismo: estudo em DNA de células de mucosa oral e sangue periférico extraído com NaCI / Analysis of PROP1 gene in patients with hypopituitarism: study in DNA from blood and oral cells extracted with NaCI

O objetivo foi estudar as mutações no PROP1 e padronizar a extração de DNA de células de swab oral, com NaCl e comparar com um kit comercial. Identificamos a mutação 301-302delAG em 6 pacientes e a mutação G51A em em um paciente. A deleção completa do PROP1 foi encontrada em dois irmãos, filhos de pais consangüíneos. Para confirmar a deleção do PROP1, o Southern blotting foi realizado usando como sonda o produto de PCR do exon 2 do PROP1 e um fragmento do CYP21A2 como sonda controle. A banda referente ao CYP21A2 estava presente nos pacientes e controles e a banda referente ao PROP1 estava ausente nos irmãos e presente na mãe e nos controles / Our objective was to study PROP1 mutations and standardize DNA extraction from an oral swab, with NaCl method, comparing it with a commercial kit. We identified the delAG301-302 mutation in 6 patients and G51A mutation in a single patient. We report here a complete deletion of PROP1 found in two siblings, born to consanguineous parents. To confirm the hypothesis of PROP1 gene deletion, Southern blotting was performed using PROP1 exon 2 gene PCR product as a probe and a fragment of CYP21A2 gene as a control probe. The CYP21A2 band was present in patients and controls whereas PROP1 band was absent in both siblings and present in their mother and in controls. To define the extension of this deletion a number of PCRs covering this region. This allowed us determine the deleted region from 9.6 kb upstream to 11 kb downstream of PROP with a maximum deletion size of 18.4 kb. Both methods yielded good quality DNA, allowing the amplification of 3 exons of PROP1 gene...