Project description:This study was designed to identify the sRNAs in Aphis gossypii (cotton-melon aphid) during Vat-mediated resistance in teraction with melon
Project description:Investigation of whole genome gene expression level changes in Ashbya gossypii VTT D-101398 secreting recombinant endoglucanase I (EGI) from Trichoderma ressei (Ribeiro et al. 2010 - PMID: 20422178), compared to the its corresponding empty vector control strain and to conditions where VTT D-101398 EGI secreting cultures were treated with dithiothreitol (DTT). Background: Ashbya gossypii is a filamentous Saccharomycete used for the industrial production of riboflavin that has been recently explored as a host system for recombinant protein production. To gain insight into the protein secretory pathway of this biotechnologically relevant fungus, we undertook genome-wide analyses to explore its secretome and its transcriptional responses to protein secretion stress. Results: A computational pipeline was used to predict the inventory of proteins putatively secreted by A. gossypii via the general secretory pathway. The proteins actually secreted by this fungus into the supernatants of submerged cultures in minimal and rich medium were mapped by two-dimensional gel electrophoresis, revealing that most of the A. gossypii secreted proteins have an isoelectric point between 4 and 6, and a molecular mass above 25 kDa. These analyses together indicated that 1-4% of A. gossypii proteins are likely to be secreted, of which less than 33% are putative hydrolases. Furthermore, transcriptomic analyses carried out in A. gossypii cells under recombinant protein secretion conditions and dithiothreitol-induced secretion stress unexpectedly revealed that a conventional unfolded protein response (UPR) was not activated in any of the conditions, as the expression levels of several well-known UPR target genes (e.g. IRE1, KAR2, HAC1 and PDI1 homologs) remained unaffected. However, several other genes involved in protein unfolding, endoplasmatic reticulum-associated degradation, proteolysis, vesicle trafficking, vacuolar protein sorting, secretion and mRNA degradation were up-regulated by dithiothreitol-induced secretion stress. Conversely, the transcription of several genes encoding secretory proteins, such as components of the glycosylation pathway, was severely repressed by dithiothreitol Conclusions: This study provides the first insights into the secretion stress response of A. gossypii, as well as a basic understanding of its protein secretion potential, which is more similar to that of yeast than to that of other filamentous fungi. Contrary to what has been widely described for yeast and fungi, a conventional UPR was not observed in A. gossypii, but alternative protein quality control mechanisms enabled it to cope with secretion stress. These data will help provide strategies for improving heterologous protein secretion in A. gossypii.
Project description:The goal of this experiment concerned the comparison of genes controling the mating and filamentation pathways in S. cerevisiae and the filamentous fungus A. gossypii. Even though the A. gossypii genome encodes homologous genes of all components of these two pathways, there are major differences in the modes of growth beween the two organisms, and the potential for mating is unknown in A. gossypii. To shed light on functional conservation the two pathway including transcriptional regulation, a bioinfomatics analysis that looked into transcription factor conservation was carried out. To experimentally investigate regulatory network conservation, the two transcription factors AgTec1. AgSte12 and the repressor AgDig1.2 that act at the end of the pathways were deleted. Subsequent comparisons of mRNA levels of the deletion mutants with wild type allowed the identification of genes and gene groups which are regulated by the transcription factors or the repressor.
Project description:In contrast to most filamentous fungi, A. gossypii displays <br>a very simple haploid life cycle. This is a transcriptome analysis <br>of A. gossypii at different developmental stages. Individual transcription profiles<br>were developed from spores to bipolar germlings (time<br>frame 9 h), from bipolar germlings to advanced mycelia<br>and to very fast growing hyphae (time frame 9h and 4 d, <br>respectively) and from very fast growing hyphae to <br>sporulating mycelium (time frame 2 d).