Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates

Depletion of Aspergillus nidulans cotA causes a severe polarity defect which is not suppressed by the nuclear migration mutation nudA2


The Aspergillus nidulans homologue of Neurospora crassa cot-1, cotA, encoding a member of the NDR protein kinase family, has been cloned and expressed under the control of the conditional alcA promoter. Depletion of CotA by repression of the alcA promoter led to a severe growth defect accompanied by loss of polarity. Germlings show greatly enlarged volume of the spores and hyphae, accompanied by an increase in number of nuclei per compartment, though the nucleus/volume ratio is not significantly altered. The depleted CotA phenotype was not suppressed by a nuclear migration mutation nudA2. Double mutants showed an additive, defective phenotype, unlike the suppression of the cot-1 ts mutation by ropy mutations seen in N. crassa, suggesting a different relationship between nuclear migration and the cot signalling pathway in A. nidulans. A functional CotA–GFP fusion protein was found in punctate regions of fluorescence similar to the distribution reported for human NDR2, and as a cap at the hyphal tip.

This is a preview of subscription content, log in to check access.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7


  1. Armitt S, McCullough W, Roberts CF (1976) Analysis of acetate non-utilizing (acu) mutants in Aspergillus nidulans. J Gen Mirobiol 92:263–282

  2. Ballance DJ, Turner G (1985) Development of a high-frequency transforming vector for Aspergillus nidulans. Gene 36:321–331

  3. Bidlingmaier S, Weiss EL, Seidel C, Drubin DG, Snyder M (2001) The Cbk1p pathway is important for polarized cell growth and cell separation in Saccharomyces cerevisiae. Mol Cell Biol 21:2449–2462

  4. Brakhage AA, Browne P, Turner G (1992) Regulation of Aspergillus nidulans penicillin biosynthesis and penicillin biosynthesis genes acvA and ipnA by glucose. J Bacteriol 174:3789–3799

  5. Brody H, Griffith J, Cuticchia A, Arnold J, Timberlake W (1991) Chromosome-specific recombinant DNA libraries from the fungus Aspergillus nidulans. Nucleic Acids Res 19:3105–3109

  6. Bruno KS, Tinsley JH, Minke PF, Plamann M (1996) Genetic interactions among cytoplasmic dynein, dynactin, and nuclear distribution mutants of Neurospora crassa. Proc Natl Acad Sci USA 93:4775–4780

  7. Buhr TL, Oved S, Truesdell GM, Huang C, Yarden O, Dickman MB (1996) A kinase encoding gene from Colletotrichum trifolii complements a colonial growth mutant of Neurospora crassa. Mol Gen Genet 251:565–572

  8. Chen C, Dickman MB (2002) Colletotrichum trifolii TB3 kinase, a COT1 homolog, is light inducible and becomes localized in the nucleus during hyphal elongation. Eukaryot Cell 1:626–633

  9. Clutterbuck AJ (1969) Cell volume per nucleus in haploid and diploid strains of Aspergillus nidulans. J Gen Microbiol 60:133–135

  10. Collinge AJ, Fletcher MH, Trinci APJ (1978) Physiology and cytology of septation and branching in a temperature sensitive colonial mutant (cot-1) of Neurospora crassa. Trans Br Mycol 77:107–120

  11. Devroe E, Erdjument-Bromage H, Tempst P, Silver PA (2004) Human Mob proteins regulate the NDR1 and NDR2 serine-threonine kinases. J Biol Chem 279:24444–24451

  12. Dorland S, Deegenaars ML, Stillman DJ (2000) Roles for the Saccharomyces cerevisiae SDS3, CBK1 and HYM1 genes in transcriptional repression by SIN3. Genetics 154:573–586

  13. Fiddy C, Trinci APJ (1976) Mitosis, septation, branching, and the duplication cycle in Aspergillus nidulans. J Gen Microbiol 97:169–184

  14. Gatherar IM (2004) The genetic control of hyphal morphology in Aspergillus. PhD Thesis, University of Sheffield

  15. Gatherar IM, Pollerman S, Dunn-Coleman N, Turner G (2004) Identification of a novel gene hbrB required for polarised growth in Aspergillus nidulans. Fungal Genet Biol 41:463–471

  16. Gerber HP, Seipel K, Georgiev O, Hofferer M, Hug M, Rusconi S, Schaffner W (1994) Transcriptional activation modulated by homopolymeric glutamine and proline stretches. Science 263:808–811

  17. Gorovits R, Propheta O, Kolot M, Dombradi V, Yarden O (1999) A mutation within the catalytic domain of COT1 kinase confers changes in the presence of two COT1 isoforms and in Ser/Thr protein kinase and phosphatase activities in Neurospora crassa. Fungal Genet Biol 27:264–274

  18. Gorovits R, Sjollema KA, Sietsma JH, Yarden O (2000) Cellular distribution of COT1 kinase in Neurospora crassa. Fungal Genet Biol 30:63–70

  19. Hanks SK, Quinn AM, Hunter T (1988) The protein-kinase family-conserved features and deduced phylogeny of the catalytic domains. Science 241:42–52

  20. Harris SD, Momany M (2004) Polarity in filamentous fungi: moving beyond the yeast paradigm. Fungal Genet Biol 41:391–400

  21. Harris SD, Morrell JL, Hamer JE (1994) Identification and characterisation of Aspergillus nidulans mutants defective in cytokinesis. Genetics 136:517–532

  22. Harris SD, Hamer L, Sharpless KE, Hamer JE (1997) The Aspergillus nidulans sepA gene encodes an FH1/2 protein involved in cytokinesis and the maintenance of cellular polarity. EMBO J 16:3474–3483

  23. Harris SD, Read ND, Roberson RW, Shaw B, Seiler S, Plamann M, Momany M (2005) Polarisome meets spitzenkörper: microscopy, genetics and genomics converge. Eukaryot Cell 4:225–229

  24. Justice RW, Zilian O, Woods DF, Noll M, Bryant PJ (1995) The Drosophila tumor suppressor gene warts encodes a homolog of human myotonic dystrophy kinase and is required for the control of cell shape and proliferation. Genes Dev 9:534–546

  25. Kaminsky SGW, Hamer JE (1998) hyp loci control cell pattern formation in the vegetative mycelium of Aspergillus nidulans. Genetics 148:669–680

  26. Kumar S, Tamura K, Nei M (2004) MEGA3: integrated software for molecular evolutionary genetics analysis and sequence alignment. Brief Bioinform 5:150–163

  27. Lauter FR, Marchfelder U, Russo VE, Yamashiro CT, Yatzkan E, Yarden O (1998) Photoregulation of cot-1, a kinase-encoding gene involved in hyphal growth in Neurospora crassa. Fungal Genet Biol 23:300–310

  28. Maniatis T, Fritsch EF, Sambrook J (1989) Molecular cloning: a laboratory manual. Cold Spring Harbor Laboratory Press, Cold Spring Harbor

  29. Millward T, Cron P, Hemmings BA (1995) Molecular cloning and characterization of a conserved nuclear serine(threonine) protein kinase. Proc Natl Acad Sci USA 92:5022–5026

  30. Mitchell MB, Mitchell HK (1954) A partial map of linkage group D in Neurospora crassa. Proc Natl Acad Sci USA 40:436–440

  31. Momany M (2002) Polarity in filamentous fungi: establishment, maintenance and new axes. Curr Opin Microbiol 5:580–585

  32. Momany M, Westfall PJ, Abramowsky G (1999) Aspergillus nidulans swo mutants show defects in polarity establshment, polarity maintenance and hyphal morphogenesis. Genetics 151:557–567

  33. Morris NR (1975) Mitotic mutants of Aspergillus nidulans. Genet Res 26:237–254

  34. Nasr F, Becam AM, Herbert CJ (1996) The sequence of 36.8 kb from the left arm of chromosome XIV reveals 24 complete open reading frames: 18 correspond to new genes, one of which encodes a protein similar to the human myotonic dystrophy kinase. Yeast 12:169–175

  35. Nayak T, Szewczyk E, Oakley CE, Osmani A, Ukil L, Murray SL, Hynes MJ, Osmani SA, Oakley BR (2006) A versatile and efficient gene targeting system for Aspergillus nidulans. Genetics (in press)

  36. O’ Conallain C, Doolin MT, Taggart C, Thornton F, Butler G (1999) Regulated nuclear localisation of the yeast transcription factor Ace2p controls expression of chitinase (CTS1) in Saccharomyces cerevisiae. Mol Gen Genet 262:275–282

  37. Pearson CL, Xu K, Sharpless KE, Harris SD (2004) MesA, a novel fungal protein required for the stabilization of polarity axes in Aspergillus nidulans. Mol Biol Cell 15:3658–3672

  38. Plamann M, Minke PF, Tinsley JH, Bruno KS (1994) Cytoplasmic dynein and actin-related protein Arp1 are required for normal nuclear distribution in filamentous fungi. J Cell Biol 127:139–149

  39. Pontecorvo G, Roper JA, Hemmons LM, MacDonald K, Bufton AWJ (1953) The genetics of Aspergillus nidulans. Adv Genet 5:141–239

  40. Prade RA, Griffith J, Kochut K, Arnold J, Timberlake WE (1997) In vitro reconstruction of the Aspergillus (=Emericella) nidulans genome. Proc Natl Acad Sci USA 94:14564–14569

  41. Racki WJ, Becam AM, Nasr F, Herbert CJ (2000) Cbk1p, a protein similar to the human myotonic dystrophy kinase, is essential for normal morphogenesis in Saccharomyces cerevisiae. EMBO J 19:4524–4532

  42. Ramon A, MuroPastor MI, Scazzocchio C, Gonzalez R (2000) Deletion of the unique gene encoding a typical histone H1 has no apparent phenotype in Aspergillus nidulans. Mol Microbiol 35:223–233

  43. Scheffer J, Ziv C, Yarden O, Tudzynski P (2005) The COT1 homologue CPCOT1 regulates polar growth and branching and is essential for pathogenicity in Claviceps purpurea. Fungal Genet Biol 42:107–118

  44. Seiler S, Plamann M (2003) The genetic basis of cellular morphogenesis in the filamentous fungus Neurospora crassa. Mol Biol Cell 14:4352–4364

  45. Shi X, Sha Y, Kaminskyj S (2004) Aspergillus nidulans hypA regulates morphogenesis through the secretion pathway. Fungal Genet Biol 41:75–88

  46. Steele GC, Trinci APJ (1977) Effect of temperature and temperature shifts on growth and branching of a wild type and a temperature sensitive colonial mutant (cot-1) of Neurospora crassa. Arch Microbiol 113:43–48

  47. Trinci APJ (1979) The duplication cycle and branching in fungi. In: Burnett JH, Trinci APJ (eds) Fungal walls and hyphal growth. Cambridge University Press, Cambridge, pp 319–358

  48. Verde F, Wiley DJ, Nurse P (1998) Fission yeast orb6, a ser/thr protein kinase related to mammalian rho kinase and myotonic dystrophy kinase, is required for maintenance of cell polarity and co-ordinates cell morphogenesis with the cell cycle. Proc Natl Acad Sci USA 95:7526–7531

  49. Waring RB, May GS, Morris NR (1989) Characterisation of an inducible expression system in Aspergillus nidulans using alcA and tubulin-coding genes. Gene 79:119–130

  50. Wolkow TD, Harris SD, Hamer JE (1996) Cytokinesis in Aspergillus nidulans is controlled by cell size, nuclear positioning and mitosis. J Cell Sci 109:2179–2188

  51. Xiang X, Fischer R (2004) Nuclear migration and positioning in filamentous fungi. Fungal Genet Biol 41:411–419

  52. Xiang X, Beckwith SM, Morris NR (1994) Cytoplasmic dynein is involved in nuclear migration in Aspergillus nidulans. Proc Natl Acad Sci USA 91:2100–2104

  53. Xiang X, Roghi C, Morris NR (1995) Characterisation and localisation of the cytoplasmic dynein heavy chain in A. nidulans. Proc Natl Acad Sci USA 92:9890–9894

  54. Yang L, Ukil L, Osmani A, Nahm F, Davies J, De Souza CP, Dou X, Perez-Balaguer A, Osmani SA (2004) Rapid production of gene replacement constructs and generation of a green fluorescent protein-tagged centromeric marker in Aspergillus nidulans. Eukaryot Cell 3:1359–1362

  55. Yarden O, Plamann M, Ebbole DJ, Yanofsky C (1992) cot-1, a gene required for hyphal elongation in Neurospora crassa, encodes a protein kinase. EMBO J 11:2159–2166

  56. Yu JH, Hamari Z, Han KH, Seo JA, Reyes-Dominguez Y, Scazzocchio C (2004) Double-joint PCR: a PCR-based molecular tool for gene manipulations in filamentous fungi. Fungal Genet Biol. 41:973–981

  57. Zallen JA, Peckol EL, Tobin DM, Bargmann CI (2000) Neuronal cell shape and neurite initiation are regulated by the Ndr kinase SAX-1, a member of the Orb6/COT-1/warts serine/threonine kinase family. Mol Biol Cell 11:3177–3190

  58. Zarrin M, Leeder AC, Turner G (2005) A rapid method for promoter exchange in Aspergillus nidulans using recombinant PCR. Fungal Genet Biol 42:1–8

Download references


This work was supported by BBSRC grant 50/G06623 to GT, BBSRC studentships to SJ and ACL and a Ministry of Culture and Higher Education of Iran studentship to MS. We thank Mrs. J. Price and Ms. N. Frima for technical assistance. All genetic manipulation experiments were carried out in accordance with local regulations.

Author information

Correspondence to Geoffrey Turner.

Additional information

Communicated by P. Punt.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Johns, S.A., Leeder, A.C., Safaie, M. et al. Depletion of Aspergillus nidulans cotA causes a severe polarity defect which is not suppressed by the nuclear migration mutation nudA2 . Mol Genet Genomics 275, 593 (2006).

Download citation


  • Aspergillus nidulans
  • Polarity
  • Protein kinase
  • GFP
  • Nuclear migration