Summary
This project aims at understanding the principles regulating peroxisome abundance in the penicillin producing fungus Penicillium chrysogenum. Peroxisomes are crucial for penicillin production as they contain the final steps of the penicillin biosynthetic machinery. Comparison of various P. chrysogenum strains revealed a correlation between peroxisome numbers and the level of penicillin production. Also, a P. chrysogenum strain in which peroxisome numbers were artificially increased by overproduction of a single protein, displayed a 2 to 3-fold enhanced penicillin production.
We will build on to these achievements using novel organelle proteomics approaches. Recent data in the group have demonstrated that peroxisome proliferation predominantly occurs at a peroxisomal reticulum located in the tip of growing hyphae. As in sub-apical cells peroxisome proliferation is not observed, the activity of the peroxisome reticulum in tip cells determines organelle abundance in hyphal cells. We will compare the peroxisomal proteome in P. chrysogenum hyphal tip cells with that of sub-apical cells. These cells will be separated using novel laser micro-dissection methods.
In addition, we aim to develop novel tools to isolate ultra-pure peroxisome fractions for organelle proteomic using fluorescence activated cell sorting (FACS) approaches. We will use this approach to isolate peroxisomes from selected P. chrysogenum strains that show differences in peroxisome numbers.
Both novel approaches will undoubtedly lead to important information on the machinery of peroxisome proliferation in P. chrysogenum and enable us to construct novel and improved P. chrysogenum cell factories for peptides and antibiotics.