Research Interests
Our research focuses on the regulation of morphogenesis in the filamentous fungus Aspergillus nidulans. Spores from this fungus germinate to form long tubular hyphae that are composed of multinucleate cells. Whereas the hyphal tip cell is actively engaged in the duplication cycle, the remaining subapical cells lie dormant until they form a branch. The morphogenetic events involved in the formation of nidulans hyphae include the establishment and maintenance of cellular polarity and the partitioning of hyphae through the formation of septa. Our goal is to dissect the molecular mechanisms underlying these morphogenetic events using a combinbation of genetic, molecular, genomic, and biochemical approaches. In addition, we have recently uncovered an intimate link between hyphal morphogenesis and the nidulans DNA damage response, and are using a similar set of approaches to further understand the molecular basis of this link. Since A. nidulans is a close relative of many economically important plant pathogenic fungi, our research will provide key insights into the morphogenetic events underlying pathogenesis. Moreover, the experimental tractability of A. nidulans makes it an excellent model system for characterizing eukaryotic cellular processes. In particular, the organization and structure of fungal hyphae is strikingly similar to that of several plant cell types, including pollen tubes, root hairs and trichomes. Accordingly, our research should also identify key regulators of these processes.
Recent Papers
1. Harris, S. D., and M. Momany, 2004. Polarity in filamentous fungi: moving beyond the yeast paradigm. Fungal Genet. Biol. 41: 391-400.
2. Pearson, C. P., K. Xu, K. Sharpless, and S. D. Harris, 2004. MesA, a novel fungal protein required for the stabilization of polarity axes in Aspergillus nidulans. Mol. Biol. Cell. 15: 3658-3672.
3. Gygax, S. E., C. P. Semighini, G. H. Goldman, and S. D. Harris, 2005. SepBCTF4 is required for the formation of DNA damage-induced UvsCRAD51 foci in Aspergillus nidulans. Genetics. 169: 1391-1402.
4. Harris, S. D., N. D. Read, R. W. Roberson, B. Shaw, S. Seiler, M. Plamann, and M. Momany, 2005. Spitzenkorper meets polarisome: microscopy, genetics, and genomics converge. Euk. Cell. 4: 225-229.
5. Fagundes, M. R. K., C. P. Semighini, I. Malavazi, M. Savoldi, J. F. Lima, M. H. Goldman, S. D. Harris, and G. H. Goldman, 2005. The Aspergillus nidulans uvsBATR and scaANBS1 genes show genetic interactions during recovery from replication stress and DNA damage. Euk. Cell. 4: 1239-1252.
6. Harris, S. D., 2005. Morphogenesis in germinating Fusarium graminearum macroconidia. Mycologia 97: 880-887.
7. Galagan, J. E. et al. (49 authors; #18, S. D. Harris), 2005. Sequencing and comparative analysis of Aspergillus nidulans. Nature. 438: 1105-1115.
8. Virag, A., and S. D. Harris, 2006. The Spitzenkorper: a molecular perspective. Mycological Res. 110: 4-13.
9. Semighini, C. P., J. M. Hornby, R. Dumitru, K. W. Nickerson, and S. D. Harris, 2006. Farnesol-induced apoptosis in Aspergillus nidulans reveals a possible mechanism for antagonistic interactions between fungi. Mol. Microbiol. 59: 753-764.
10. Li, S., L. Du, G. Yuen, and S. D. Harris, 2006. Distinct ceramide synthases regulate polarized growth in the filamentous fungus Aspergillus nidulans. Mol. Biol. Cell. 17: 1218-1227
11. Malavazi, I., C. P. Semighini, M. R. Z. Kress, S. D. Harris, and G. H. Goldman, 2006. Regulation of hyphal morphogenesis and the DNA damage response by the Aspergillus nidulans ATM homologue, AtmA. Genetics. 173: 99-109.
12. Semighini, C. P., M. Savoldi, G. H. Goldman, and S. D. Harris, 2006. Functional characterization of the Aspergillus nidulans poly (ADP-ribose) polymerase homologue, PrpA. Genetics. 173: 87-98.
13. Virag, A., and S. D. Harris, 2006. Functional characterization of the Aspergillus nidulans homologues of yeast Spa2 and Bud6. Eukaryot. Cell. 5: 881-895.
14. Harris, S. D., 2006. Cell polarity in filamentous fungi: shaping the mold. Intl. Rev. Cytol. 251: 41-77.
15. Forgue, P., S. Halouska, M. Werth, K. Xu, S. Harris, and R. Powers, 2006. NMR metabolic profiling of Aspergillus nidulans to monitor drug and protein activity. J. Proteome Res. 5: 1916-1923.
16. Malavazi, I., M. Savoldi, S. M. Z. Di Mauro, C. F. M. Menck, S. D. Harris, M. H. Goldman, and G. H. Goldman. 2006. Transcriptome analysis of Aspergillus nidulans exposed to camptothecin-induced DNA damage. Eukaryot. Cell 5: 1688-1704.
17. Ferreira, M. E., T. Heinekamp, A. Hartl, A. A. Brakhage, C. P. Semighini, S. D. Harris, M. Savoldi, P. F. de Gouvea, M. H. Goldman, and G. H. Goldman. 2006. Functional characterization of the Aspergillus fumigatus calcineurin. Fungal Genet. Biol. 43: 219-230
18. Yu, F., K. Zaleta-Rivera, X. Zhu, J. Huffman, J. C. Millet, S. D. Harris, G. Yuen, X. C. Li, and L. Du. 2007. Structure and biosynthesis of heat-stable antifungal factor (HSAF), a broad-spectrum antimycotic with a novel mode of action. Antimicrob. Agents Chemother. 51: 64-72.
19. Li, S., D. Bao, G. Yuen, S. D. Harris, and A. Calvo. 2007. basA regulates cell organization and asexual/sexual sporulation ratio in Aspergillus nidulans. Genetics 176: 243-253.
20. Virag, A., M. P. Lee, H. Si, and S. D. Harris. 2007. Regulation of hyphal morphogenesis by Cdc42 and Rac1 homologues in Aspergillus nidulans. Mol. Microbiol. 66: 1579-1596
21. Semighini, C. P., N. Murray, and S. D. Harris. 2008. Inhibition of Fusarium graminearum growth and development by farnesol. FEMS Microbiology Lett. 279: 259-264.
22. Rittenour, W. R., and S. D. Harris. 2007. Characterization of Fusarium graminearum Mes1 reveals roles in cell surface organization and virulence. Fungal Genet. Biol. 45: 933-946.
23. Semighini, C. P, and S. D. Harris. 2008. Regulation of apical dominance in Aspergillus nidulans hyphae by reactive oxygen species. Genetics. 179: 1919-1932.
24. Li, S., C. C. Jochum, F. Yu, K. Zaleta-Rivera, L. Du, S. D. Harris, and G. Y. Yuen. 2008. An antibiotic complex from Lysobacter enzymogenes strain C3: antimicrobial activity and role in plant disease control. Phytopathology. 98: 695-701.
25. Pollack, J. K., S. D. Harris, and M. R. Martin. 2008. Autophagy in filamentous fungi. Fungal Genet. Biol. in press (doi:10.1016/j.fgb.2008.10.010).
26. Harris, S. D., G. Turner, V. Meyer, E. A. Espeso, T. Specht, N. Takeshita, and K. Helmstedt. Morphology and development in Aspergilus nidulans: a complex puzzle. Fungal Genet. Biol. in press (doi:10.1016/j.fgb.2008.07.023).
27. Harris, S. D. 2008. Branching of fungal hyphae: regulation, mechanisms and comparison with other branching systems. Mycologia. In press (doi:10.3852/08-177)(cover image).
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