Abstract
The phytopathogenic fungus Ustilago maydis exists in two stages, the yeast-like haploid form and the filamentous dikaryon. Both pathogenicity and dimorphism are genetically controlled by two mating-type loci, with only the filamentous stage being pathogenic on corn. We have identified two genes (kin1 and kin2) encoding motor proteins of the kinesin family. Kin1 is most similar to the human CENP-E gene product, while Kin2 is most closely related to the conventional kinesin Nkin of Neurospora crassa. Deletion mutants of kin1 had no discernible phenotype; delta kin2 mutants, however, were severely affected in hyphal extension and pathogenicity. The wild-type dikaryon showed rapid tip growth, with all the cytoplasm being moved to the tip compartment. Left behind are septate cell wall tubes devoid of cytoplasm. In delta kin2 mutants, dikaryotic cells were formed after cell fusion, but these hyphal structures remained short and filled with cytoplasm. A functional green fluorescent protein (GFP)-Kin2 fusion was generated and used to determine the localization of the motor protein by fluorescence microscopy. Inspection of the hyphal tips by electron microscopy revealed a characteristic accumulation of darkly stained vesicles which was absent in mutant cells. We suggest that the motor protein Kin2 is involved in organizing this specialized growth zone at the hyphal tip, probably by affecting the vectorial transport of vesicles.
Full Text
The Full Text of this article is available as a PDF (1.0 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Altschul S. F., Gish W., Miller W., Myers E. W., Lipman D. J. Basic local alignment search tool. J Mol Biol. 1990 Oct 5;215(3):403–410. doi: 10.1016/S0022-2836(05)80360-2. [DOI] [PubMed] [Google Scholar]
- Banuett F. Genetics of Ustilago maydis, a fungal pathogen that induces tumors in maize. Annu Rev Genet. 1995;29:179–208. doi: 10.1146/annurev.ge.29.120195.001143. [DOI] [PubMed] [Google Scholar]
- Banuett F., Herskowitz I. Different a alleles of Ustilago maydis are necessary for maintenance of filamentous growth but not for meiosis. Proc Natl Acad Sci U S A. 1989 Aug;86(15):5878–5882. doi: 10.1073/pnas.86.15.5878. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bloom G. S., Endow S. A. Motor proteins 1: kinesins. Protein Profile. 1995;2(10):1105–1171. [PubMed] [Google Scholar]
- Chalfie M., Tu Y., Euskirchen G., Ward W. W., Prasher D. C. Green fluorescent protein as a marker for gene expression. Science. 1994 Feb 11;263(5148):802–805. doi: 10.1126/science.8303295. [DOI] [PubMed] [Google Scholar]
- Chiu W., Niwa Y., Zeng W., Hirano T., Kobayashi H., Sheen J. Engineered GFP as a vital reporter in plants. Curr Biol. 1996 Mar 1;6(3):325–330. doi: 10.1016/s0960-9822(02)00483-9. [DOI] [PubMed] [Google Scholar]
- Day P. R., Anagnostakis S. L. Corn smut dikaryon in culture. Nat New Biol. 1971 May 5;231(18):19–20. doi: 10.1038/newbio231019a0. [DOI] [PubMed] [Google Scholar]
- Enos A. P., Morris N. R. Mutation of a gene that encodes a kinesin-like protein blocks nuclear division in A. nidulans. Cell. 1990 Mar 23;60(6):1019–1027. doi: 10.1016/0092-8674(90)90350-n. [DOI] [PubMed] [Google Scholar]
- Harris G. S., Keath E. J., Medoff J. Characterization of alpha and beta tubulin genes in the dimorphic fungus Histoplasma capsulatum. J Gen Microbiol. 1989 Jul;135(7):1817–1832. doi: 10.1099/00221287-135-7-1817. [DOI] [PubMed] [Google Scholar]
- Hartmann H. A., Kahmann R., Bölker M. The pheromone response factor coordinates filamentous growth and pathogenicity in Ustilago maydis. EMBO J. 1996 Apr 1;15(7):1632–1641. [PMC free article] [PubMed] [Google Scholar]
- Hoffman C. S., Winston F. A ten-minute DNA preparation from yeast efficiently releases autonomous plasmids for transformation of Escherichia coli. Gene. 1987;57(2-3):267–272. doi: 10.1016/0378-1119(87)90131-4. [DOI] [PubMed] [Google Scholar]
- Holden D. W., Kronstad J. W., Leong S. A. Mutation in a heat-regulated hsp70 gene of Ustilago maydis. EMBO J. 1989 Jul;8(7):1927–1934. doi: 10.1002/j.1460-2075.1989.tb03596.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Keon J. P., White G. A., Hargreaves J. A. Isolation, characterization and sequence of a gene conferring resistance to the systemic fungicide carboxin from the maize smut pathogen, Ustilago maydis. Curr Genet. 1991 Jun;19(6):475–481. doi: 10.1007/BF00312739. [DOI] [PubMed] [Google Scholar]
- Kämper J., Reichmann M., Romeis T., Bölker M., Kahmann R. Multiallelic recognition: nonself-dependent dimerization of the bE and bW homeodomain proteins in Ustilago maydis. Cell. 1995 Apr 7;81(1):73–83. doi: 10.1016/0092-8674(95)90372-0. [DOI] [PubMed] [Google Scholar]
- Meluh P. B., Rose M. D. KAR3, a kinesin-related gene required for yeast nuclear fusion. Cell. 1990 Mar 23;60(6):1029–1041. doi: 10.1016/0092-8674(90)90351-e. [DOI] [PubMed] [Google Scholar]
- Plamann M., Minke P. F., Tinsley J. H., Bruno K. S. Cytoplasmic dynein and actin-related protein Arp1 are required for normal nuclear distribution in filamentous fungi. J Cell Biol. 1994 Oct;127(1):139–149. doi: 10.1083/jcb.127.1.139. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sanger F., Nicklen S., Coulson A. R. DNA sequencing with chain-terminating inhibitors. Proc Natl Acad Sci U S A. 1977 Dec;74(12):5463–5467. doi: 10.1073/pnas.74.12.5463. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Snetselaar KM, Bolker M, Kahmann R. Ustilago maydis Mating Hyphae Orient Their Growth toward Pheromone Sources. Fungal Genet Biol. 1996 Dec;20(4):299–312. doi: 10.1006/fgbi.1996.0044. [DOI] [PubMed] [Google Scholar]
- Spellig T., Bottin A., Kahmann R. Green fluorescent protein (GFP) as a new vital marker in the phytopathogenic fungus Ustilago maydis. Mol Gen Genet. 1996 Oct 16;252(5):503–509. doi: 10.1007/BF02172396. [DOI] [PubMed] [Google Scholar]
- Spellig T., Bölker M., Lottspeich F., Frank R. W., Kahmann R. Pheromones trigger filamentous growth in Ustilago maydis. EMBO J. 1994 Apr 1;13(7):1620–1627. doi: 10.1002/j.1460-2075.1994.tb06425.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Steinberg G., Schliwa M. Organelle movements in the wild type and wall-less fz;sg;os-1 mutants of Neurospora crassa are mediated by cytoplasmic microtubules. J Cell Sci. 1993 Oct;106(Pt 2):555–564. doi: 10.1242/jcs.106.2.555. [DOI] [PubMed] [Google Scholar]
- Steinberg G., Schliwa M. The Neurospora organelle motor: a distant relative of conventional kinesin with unconventional properties. Mol Biol Cell. 1995 Nov;6(11):1605–1618. doi: 10.1091/mbc.6.11.1605. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tsukuda T., Carleton S., Fotheringham S., Holloman W. K. Isolation and characterization of an autonomously replicating sequence from Ustilago maydis. Mol Cell Biol. 1988 Sep;8(9):3703–3709. doi: 10.1128/mcb.8.9.3703. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Urban M., Kahmann R., Bölker M. Identification of the pheromone response element in Ustilago maydis. Mol Gen Genet. 1996 Apr 24;251(1):31–37. doi: 10.1007/BF02174341. [DOI] [PubMed] [Google Scholar]
- Yen T. J., Compton D. A., Wise D., Zinkowski R. P., Brinkley B. R., Earnshaw W. C., Cleveland D. W. CENP-E, a novel human centromere-associated protein required for progression from metaphase to anaphase. EMBO J. 1991 May;10(5):1245–1254. doi: 10.1002/j.1460-2075.1991.tb08066.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
