GAP aflR- vs WT timecourse
Ontology highlight
ABSTRACT:
ORGANISM(S): Aspergillus flavus Aspergillus parasiticus
PROVIDER: GSE2709 | GEO | 2006/06/01
SECONDARY ACCESSION(S): PRJNA92361
REPOSITORIES: GEO
Similar Datasets
Project description:The carcinogen aflatoxin is synthesized by a cluster of genes that are regulated by the transcriptional factor, AflR. Most, but not all of these genes, have a consensus binding site for AflR in their 5â untranslated region. Because aflR resides within the biosynthetic cluster, is has been suggested that it regulates only genes within the cluster. The objective of this study was to identify those genes transcriptionally regulated by AflR and to determine if any of those genes reside outside the aflatoxin biosynthetic cluster. To address this objective, we employed a cDNA microarray of 5,002 genes from Aspergillus flavus to monitor the expression of genes in a wild type and an aflR deletion strain of A. parasiticus. Keywords = aspergillus Keywords = aflatoxin Keywords = regulation Keywords = secondary metabolism
2010-06-10 | E-GEOD-2709 | biostudies-arrayexpress
Project description:Aflatoxins are toxic and carcinogenic secondary metabolites produced by the fungi Aspergillus flavus and A. parasiticus. In order to better understand the molecular mechanisms that regulate aflatoxin production, the biosynthesis of the toxin in A. flavus and A. parasticus grown in yeast extract sucrose media supplemented with 50 mM tryptophan (Trp) were examined. A. flavus grown in the presence of 50 mM tryptophan was found to have significantly reduced aflatoxin B1 and B2 biosynthesis, while A. parasiticus cultures had significantly increased B1 and G1 biosynthesis. Microarray analysis of RNA extracted from fungi grown under these conditions revealed seventy seven genes that are expressed significantly different between A. flavus and A. parasiticus, including the aflatoxin biosynthetic genes aflD (nor-1), aflE (norA), and aflO (omtB). It is clear that the regulatory mechanisms of aflatoxin biosynthesis in response to Trp in A. flavus and A. parasiticus are different. These candidate genes may serve as regulatory factors of aflatoxin biosynthesis. Keywords: Aflatoxin, Aspergillus, flavus, Amnio Acids, Tryptophan
2007-06-07 | GSE6182 | GEO
Project description:Objective: Aspergillus flavus aflR, a gene encoding a Zn(II)2Cys6 DNA-binding domain, is an important transcriptional regulator of the aflatoxin biosynthesis gene cluster. Our previous results of GO analysis for the binding sites of AflR in A. flavus suggest that AflR may play an integrative regulatory role. This study aimed to investigate the integrative function of the aflR gene in A. flavus. Design: In this study, we used Aspergillus flavus NRRL3357 as a wild-type strain (WT) and constructed a knockout strain of A. flavus ΔaflR by homologous recombination. Based on the transcriptomics technology, we investigated the metabolic effects of aflR gene on growth, development and toxin synthesis of A. flavus, and discussed the overall regulation mechanism of aflR gene on A. flavus at the transcriptional level. Results: The disruption of aflR severely affected the aflatoxin biosynthetic pathway, resulting in a significant decrease in aflatoxin production. In addition, disrupted strains of the aflR gene produced relatively sparse conidia and a very small number of sclerotia. However, the biosynthesis of cyclopiazonic acid (CPA) was not affected by aflR gene disruption. Transcriptomic analysis of the ΔaflR strain grown on potato dextrose agar (PDA) plates at 0 h, 24 h, and 72 h showed that expression of clustering genes involved in the biosynthesis of aflatoxin was significantly down-regulated. Meanwhile, the ΔaflR strain showed significant expression differences in genes involved in spore germination, sclerotial development, and carbohydrate metabolism compared to the WT strain. Conclusions: The results showed that the A. flavus aflR gene also played a positive role in the growth and development of fungi.
2021-07-16 | GSE179978 | GEO
Project description:We report here the AflR binding motif of Aspergillus flavus for the first time with the aid of ChIP-seq analysis. Of the 540 peak sequences associated with AflR binding events, 66.8% were located within 2 kb upstream (promoter region) of translational start sites. The identified 18-bp binding motif was a perfect palindromic sequence, 5′-CSSGGGWTCGAWCCCSSG’3′ with S representing G or C and W representing A or T. On closer examination, we hypothesized that the 18-bp motif sequence identified contained two identical parts (here called motif A and motif B). Motif A was in positions 8–18 on the upper strand, while motif B was in positions 11-1 on the bottom strand. The inferred length and sequence of the putative motif identified in A. flavus were similar to previous findings in A. parasiticus and A. nidulans. Gene ontology analysis indicated that AflR bound to other genes outside the aflatoxin biosynthetic gene cluster.
2020-05-02 | GSE149696 | GEO
Project description:Gene expression analysis of A. parasiticus grown under conditions conducive and nonconductive for aflatoxin production was evaluated using glass slide microarrays containing the 753 ESTs. A complex regulatory network governs the biosynthesis of aflatoxin. While several genes involved in aflatoxin production are known, their action alone cannot account for its regulation. Arrays of clones from an Aspergillus flavus cDNA library and glass slide microarrays of ESTs were screened to identify additional genes. An initial screen of the cDNA clone arrays lead to the identification of 753 unique ESTs. Many showed sequence similarity to known metabolic and regulatory genes; however, no function could be ascribed to over 50% of the ESTs. Gene expression analysis of Aspergillus parasiticus grown under conditions conducive and non-conductive for aflatoxin production was evaluated using glass slide microarrays containing the 753 ESTs. Twenty-four genes were more highly expressed during aflatoxin biosynthesis and 18 genes were more highly expressed prior to aflatoxin biosynthesis. No predicted function could be ascribed to 18 of the 24 genes whose elevated expression was associated with aflatoxin biosynthesis. Keywords = Aspergillus Keywords = aflatoxin Keywords: time-course
2003-01-15 | E-GEOD-204 | biostudies-arrayexpress
Project description:Gene expression analysis of A. parasiticus grown under conditions conducive and nonconductive for aflatoxin production was evaluated using glass slide microarrays containing the 753 ESTs. A complex regulatory network governs the biosynthesis of aflatoxin. While several genes involved in aflatoxin production are known, their action alone cannot account for its regulation. Arrays of clones from an Aspergillus flavus cDNA library and glass slide microarrays of ESTs were screened to identify additional genes. An initial screen of the cDNA clone arrays lead to the identification of 753 unique ESTs. Many showed sequence similarity to known metabolic and regulatory genes; however, no function could be ascribed to over 50% of the ESTs. Gene expression analysis of Aspergillus parasiticus grown under conditions conducive and non-conductive for aflatoxin production was evaluated using glass slide microarrays containing the 753 ESTs. Twenty-four genes were more highly expressed during aflatoxin biosynthesis and 18 genes were more highly expressed prior to aflatoxin biosynthesis. No predicted function could be ascribed to 18 of the 24 genes whose elevated expression was associated with aflatoxin biosynthesis. Keywords = Aspergillus Keywords = aflatoxin Keywords: time-course
2003-01-15 | GSE204 | GEO
Project description:To better understand the effect of temperature on mycotoxin biosynthesis, RNA-Seq technology was used to profile the Aspergillus flavus transcriptome under different temperature conditions. This approachallowed us to quantify transcript abundance for over 80% of fungal genes including 1,153 genes that were differentially expressed at 30M-BM-0C and 37M-BM-0C. Wleven of the 55 secondary metabolite clusters were up-regulated at the lower temperature, including aflatoxin biosynthesis genes, which were among the most highly up-expressed genes. On average, transcript abundance for the 30 aflatoxin biosynthesis genes was 3,300 times greater at 30M-BM-0C as compared to 37M-BM-0C. The results are consistent with the view that high temperature negatively affects aflatoxin production by turning down transcription of the two key transcriptional regulators, aflR and aflS. Subtle changes in the expression levels of aflS to aflR appear to control transcription activation of the aflatoxin cluster. 2 samples examined: from the fungus grown at 30M-BM-0C and 37M-BM-0C
2011-06-16 | E-GEOD-30031 | biostudies-arrayexpress
Project description:To better understand the effect of temperature on mycotoxin biosynthesis, RNA-Seq technology was used to profile the Aspergillus flavus transcriptome under different temperature conditions. This approachallowed us to quantify transcript abundance for over 80% of fungal genes including 1,153 genes that were differentially expressed at 30°C and 37°C. Wleven of the 55 secondary metabolite clusters were up-regulated at the lower temperature, including aflatoxin biosynthesis genes, which were among the most highly up-expressed genes. On average, transcript abundance for the 30 aflatoxin biosynthesis genes was 3,300 times greater at 30°C as compared to 37°C. The results are consistent with the view that high temperature negatively affects aflatoxin production by turning down transcription of the two key transcriptional regulators, aflR and aflS. Subtle changes in the expression levels of aflS to aflR appear to control transcription activation of the aflatoxin cluster.
2011-06-16 | GSE30031 | GEO
Project description:Gene expression analysis of A. parasiticus grown under conditions conducive and nonconductive for aflatoxin production was evaluated using glass slide microarrays containing 765 ESTs. Aflatoxins (AF) produced by Aspergillus flavus and A. parasiticus are responsible for approximately $270M in losses annually in the corn, peanut, cotton, and tree nut industries of the United States. In an attempt to develop effective control procedures, research has focused on elucidating the pathway of aflatoxin biosynthesis with the goal of identifying potential targets for intervention. Research to date points to the involvement of complex and likely overlapping regulatory circuits. To better understand the regulation by nutritional and environmental factors, a targeted cDNA microarray consisting of genes associated with AF production was employed to investigate the influence of nitrogen source, carbon source, temperature, and pH on AF production. For each nutritional or environmental parameter examined, a condition conducive for aflatoxin production was compared with a condition that was non-conducive. Three replicate cultures for each condition were grown. Cultures were grown for 24 hours and harvested. AF production for each culture was quantified and tissues were stored separately at -80C. For array hybridization, tissue samples for each condition were pooled and RNA extracted using Trizol reagent. Keywords = aspergillus Keywords = aflatoxin Keywords = regulation Keywords = secondary metabolism
2010-06-10 | E-GEOD-1649 | biostudies-arrayexpress
Project description:Gene expression analysis of A. parasiticus grown under conditions conducive and nonconductive for aflatoxin production was evaluated using glass slide microarrays containing 765 ESTs. Aflatoxins (AF) produced by Aspergillus flavus and A. parasiticus are responsible for approximately $270M in losses annually in the corn, peanut, cotton, and tree nut industries of the United States. In an attempt to develop effective control procedures, research has focused on elucidating the pathway of aflatoxin biosynthesis with the goal of identifying potential targets for intervention. Research to date points to the involvement of complex and likely overlapping regulatory circuits. To better understand the regulation by nutritional and environmental factors, a targeted cDNA microarray consisting of genes associated with AF production was employed to investigate the influence of nitrogen source, carbon source, temperature, and pH on AF production. For each nutritional or environmental parameter examined, a condition conducive for aflatoxin production was compared with a condition that was non-conducive. Three replicate cultures for each condition were grown. Cultures were grown for 24 hours and harvested. AF production for each culture was quantified and tissues were stored separately at -80C. For array hybridization, tissue samples for each condition were pooled and RNA extracted using Trizol reagent. Keywords = aspergillus Keywords = aflatoxin Keywords = regulation Keywords = secondary metabolism Keywords: other
2005-01-01 | GSE1649 | GEO