Regulation of xylanase in Aspergillus phoenicis: a physiological and molecular approach

Microbial xylanolytic enzymes have a promising biotechnological potential, and are extensively applied in industries. In this study, induction of xylanolytic activity was examined in Aspergillus phoenicis. Xylanase activity induced by xylan, xylose or beta-methylxyloside was predominantly extracellular (93-97%). Addition of 1% glucose to media supplemented with xylan or xylose repressed xylanase production. Glucose repression was alleviated by addition of cAMP or dibutyryl-cAMP. These physiological observations were supported by a Northern analysis using part of the xylanase gene ApXLN as a probe. Gene transcription was shown to be induced by xylan, xylose, and beta-methylxyloside, and was repressed by the addition of 1% glucose. Glucose repression was partially relieved by addition of cAMP or dibutyryl cAMP.

A Genome-wide Screen for Neurospora crassa Transcription Factors Regulating Glycogen Metabolism

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Genes diferencialmente expressos em cana-de-açúcar inoculada com Xanthomonas albilineans, o agente causal da escaldadura da folha

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A systematic approach to identify STRE-binding proteins of the gsn glycogen synthase gene promoter in Neurospora crassa

The gene encoding glycogen synthase in Neurospora crassa (gsn) is transcriptionally down-regulated when mycelium is exposed to a heat shock from 30 to 45 degrees C. The gsn promoter has one stress response element (STRE) motif that is specifically bound by heat shock activated nuclear proteins. In this work, we used biochemical approaches together with mass spectrometric analysis to identify the proteins that bind to the STRE motif and could participate in the gsn transcription regulation during heat shock. Crude nuclear extract of heat-shocked mycelium was prepared and fractionated by affinity chromatography. The fractions exhibiting DNA-binding activity were identified by electrophoretic mobility shift assay (EMSA) using as probe a DNA fragment containing the STRE motif DNA-protein binding activity was confirmed by Southwestern analysis. The molecular mass (MM) of proteins was estimated by fractionating the crude nuclear extract by SDS-PAGE followed by EMSA analysis of the proteins corresponding to different MM intervals. Binding activity was detected at the 30-50 MM kDa interval. Fractionation of the crude nuclear proteins by IEF followed by EMSA analysis led to the identification of two active fractions belonging to the pIs intervals 3.54-4.08 and 6.77-7.31. The proteins comprising the MM and pI intervals previously identified were excised from a 2-DE gel, and subjected to mass spectrometric analysis (MALDI-TOF/TOF) after tryptic digestion. The proteins were identified by search against the MIPS and MIT N. crassa databases and five promising candidates were identified. Their structural characteristics and putative roles in the gsn transcription regulation are discussed.

Molecular mechanisms of the induction of IL-12 and its inhibition by IL- 10

Exogenously added IL-10 rapidly inhibited Staphylococcus aureus- or LPS- induced cytokine mRNA expression in human PBMCs and monocytes, with a maximal effect observed when IL-10 was added from 20 h before until 1 h after the addition of the inducers. Nuclear run-on assays revealed that the inhibition of IL-12 p40, IL-12 p35, and TNF-α was at the gene transcriptional level and that the addition of IL-10 to S. aureus- or LPS-treated PBMCs did not affect mRNA stability. The inhibitory activity of IL-10 was abrogated by cycloheximide (CHX), suggesting the involvement of a newly synthesized protein(s). The addition of CHX at 2 h before S. aureus or LPS also inhibited the accumulation of IL-12 p40 mRNA, but did not inhibit IL-12 p35 and TNF-α mRNA. This finding suggests that p40 transcription is regulated through a de novo synthesized protein factor(s), whereas the addition of CHX at 2 h after S. aureus activation caused superinduction of the IL-12 p40, IL-12 p35, and TNF-α genes. These results indicate that in human monocytes, the mechanism(s) of IL-10 suppression of both IL-12 p40 and IL-12 p35 genes is primarily seen at the transcriptional level, and that the induction of the IL-12 p40 and p35 genes have different requirements for de novo protein synthesis.

Growth hormone mRNA expression in the pituitary of Bos indicus and Bos taurus x Bos indicus crossbred young bulls treated with recombinant bovine somatotropin

The effects of breed and of recombinant bovine somatotropin (rbST) treatment on growth hormone gene expression were studied in young bulls. The experiment was completely randomized in a [2 × 2]-factorial arrangement, using two levels of rbst (0 or 250 mg/animal/14 days), and two breed groups (Nelore and Simmental x Nelore crossbred). A CDNA encoding Bos indicus growth hormone was cloned and sequenced for use as a probe in Northern and dot blot analyses. Compared to the Bos taurus structural gene, the Bos indicus CDNA was found to begin 21 bases downstream from the transcription initiation site and had only two discrepancies (C to T at position 144-His and T to C at position 354-Phe), without changes in the polypeptide sequence. However, two amino acid substitutions were found for Bubalus spp., which belong to the same tribe. The rbst treatment did not change any of the characteristics evaluated (body and pituitary gland weights, growth hormone MRNA expression level). Crossbred animals had significantly higher body weight and heavier pituitaries than Nelore cattle. Pituitary weight was proportional to body weight in both breed groups. Growth hormone MRNA expression in the pituitary was similar (P>0.075) for both breed and hormonal treatment groups, but was 31.9% higher in the pure Nelore group, suggesting that growth hormone gene transcription regulation differs among these breeds.

Identificação de proteínas ligantes de CRABP2, proteína envolvida na via de sinalização celular por ácido retinóico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Caracterização funcional dos elementos de transcrição do gene da glicogênio sintase (gsn) de Neurospora crassa

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Identificação de genes diferencialmente expressos em câncer de laringe

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

New ligands of the cellular retinoic acid-binding protein 2 (CRABP2) suggest a role for this protein in chromatin remodeling

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Transcription of the Hsp30, Hsp70, and Hsp90 heat shock protein genes is modulated by the PalA protein in response to acid pH-sensing in the fungus Aspergillus nidulans

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Signal transducer and activator of transcription 3-regulated sarcoendoplasmic reticulurn Ca2+-ATPase 2 expression by prolactin and glucocorticoids is involved in the adaptation of insulin secretory response during the peripartum period

During pregnancy, the maternal endocrine pancreas undergoes, as a consequence of placental lactogens and prolactin (PR,L) action, functional changes that are characterized by increased glucose-induced insulin secretion. After delivery, the maternal endocrine pancreas rapidly returns to nonpregnant state, which is mainly attributed to the increased serum levels of glucocorticoids (GCs). Although GCs are known to decrease insulin secretion and counteract PRL action, the mechanisms for these effects are poorly understood. We have previously demonstrated that signal transducer and activator of transcription 3 (STAT3) is increased in islets treated with PRL. In the present study, we show that STAT3 expression and serine phosphorylation are increased in pancreatic islets at the end of pregnancy (P19). STAT3 serine phosphorylation rapidly returned to basal levels 3 days after delivery (U). The expression of the sarcoendoplasmic reticulum Ca2+-ATPase 2 (SERCA2), a crucial protein involved in the regulation of calcium handling in P-cells, was also increased in P19, returning to basal levels at L3. PRL increased SERCA2 and STAT3 expressions and STAT3 serine phosphorylation in RINm5F cells. The upregulation of SERCA2 by PRL was abolished after STAT3 knockdown. Moreover, PRL-induced STAT3 serine phosphorylation and SERCA2 expression were inhibited by dexamethasone (DEX). Insulin secretion from islets of PI 9 rats pre-incubated with thapsigargin and L3 rats showed a dramatic suppression of first phase of insulin release. The present results indicate that PRL regulates SERCA2 expression by a STAT3-dependent mechanism. PRL effect is counteracted by DEX and might contribute to the adaptation of maternal endocrine pancreas during the peripartum period.

Differential regulation of MMP-13 expression in two models of experimentally induced periodontal disease in rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

HTRIdb: an open-access database for experimentally verified human transcriptional regulation interactions

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)