The main goal of the current project is the functional characterization of transcription factors that might be involved in the glycogen metabolism regulation in the fungus Neurospora crassa. In normal growth conditions this fungus accumulates glycogen at the end of the exponential phase and degrades it at the beginning of stationary phase. In a stress situation such as heat shock (30ºC to 45ºC), it is well known that the fungus degrades glycogen; the opposite is described for the yeast Saccharomyces cerevisiae in the same stress situation. Previous results from our laboratory showed that, under heat shock, transcription of the gene (gsn) that codes glycogen synthase (the synthesis regulatory enzyme) is severely reduced and recovered when the fungus returns to its normal growth temperature (30ºC). In an attempt to understand the molecular mechanisms involved in the gsn transcription regulation, the genomic sequence of the gene plus its 5´-flanking region were isolated. It was demonstrated that nuclear proteins activated after heat shock were able to recognize and to bind to DNA fragments (from promoter and 5´-UTR regions) containing regulatory DNA elements such as HSE and STRE. After sequencing the N. crassa genome, a collection of transcription factors mutant strains was available from FGSC (Fungal Genetics Stock Center, Missouri, USA). The utilization of these strains in a systematic analysis aiming to identify the transcription factors participating in the molecular mechanisms involved in the glycogen metabolism regulation is highly promising and opens new perspectives of studies to our laboratory.
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