The work presented here is part of a thematic project that aims to study the biochemical and molecular mechanisms involved in the regulation of glycogen metabolism using as model the fungus Neurospora crassa. Recently, a collection of mutant strains containing genes that encode transcription factors individually knocked-out was acquired by the laboratory. A screening was performed as an attempt to identify transcription factors involved in the regulation of glycogen metabolism, during normal growth and under a stressful condition, such as heat stress. Some strains showed a profile of glycogen accumulation distinct from the wild-type strain, and transcription factors absent in these strains were considered as potential regulators of glycogen metabolism in the fungus.Among the identified transcription factors, five are described in the literature as proteins related to the rhythm of the biological clock and/or in response to light, such as RCO-1, CSP-1, CTF-1±, SUB-1 and SAH-2 proteins. More recently, some studies have reported a connection between circadian rhythms and metabolism, that is how organisms link their nutritional and metabolic status to their biological clocks. This led us to perform experiments to investigate the correlation between glycogen metabolism and biological clock in the fungus N. crassa, which were performed by the student applying for this fellowship. It was demonstrated that in experiments that mimic the biological clock the glycogen levels vary with cyclic periods between 20 and 24 h characteristic of the N. crassa circadian rhythm. It was also shown that the expression of genes encoding glycogen synthase (gsn) and glycogen phosphorylase (gpn) regulatory enzymes is light-induced, being genes of late induction to the light. The levels of gsn and gpn transcripts appear to follow the circadian rhythm, although not as pronounced as the levels of ccg-1 transcript (positive control in the experiments). The results were discussed with the Dr. Deborah Bell-Pedersen (Department of Biology, Texas A&M University, College Station, Texas, USA), who has a large experience in the circadian clock in N. crassa and showed to be highly interested in establishing a collaborative work with us. Part of the work presented here was defined in collaboration with her and it will be conducted in her laboratory.We also plan to develop further investigation on this issue, seeking to understand which proteins might be involved in the regulation of glycogen metabolism when culture is synchronized to the biological clock and how both processes can be connected.
News published in Agência FAPESP Newsletter about the scholarship: