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  • The EMBO Journal (2002) 21, 4841 - 4850
  • doi:10.1093/emboj/cdf479

Nonself recognition is mediated by HET-C heterocomplex formation during vegetative incompatibility

Sovan Sarkar1,4, Gopal Iyer1,4, Jennifer Wu2,3 and N.Louise Glass1

  1. Plant and Microbial Biology Department, 111 Koshland Hall, University of California, Berkeley, CA 94720, USA
  2. The Biotechnology Laboratory and the Botany Department, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
  3. Present address: Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
  4. S.Sarkar and G.Iyer Contributed equally to this work

Correspondence to:

N.Louise Glass, E-mail: Lglass@uclink.berkeley.edu

Received 10 January 2002; Accepted 19 July 2002; Revised 5 July 2002

Nonself recognition during vegetative growth in filamentous fungi is mediated by heterokaryon incompatibility (het) loci. In Neurospora crassa, het-c is one of 11 het loci. Three allelic specificity groups, termed het-cOR, het-cPA and het-cGR, exist in natural populations. Heterokaryons or partial diploids that contain het-c alleles of alternative specificity show severe growth inhibition, repression of conidiation and hyphal compartmentation and death (HCD). Using epitope-tagged HET-C, we show that nonself recognition is mediated by the presence of a heterocomplex composed of polypeptides encoded by het-c alleles of alternative specificity. The HET-C heterocomplex localized to the plasma membrane (PM); PM-bound HET-C heterocomplexes occurred in all three het-c incompatible allelic interactions. Strains containing het-c constructs deleted for a predicted signal peptide sequence formed HET-C heterocomplexes in the cytoplasm and showed a growth arrest phenotype. Our finding is a step towards understanding nonself recognition mechanisms that operate during vegetative growth in filamentous fungi, and provides a model for investigating relationships between recognition mechanisms and cell death.

  • Keywords:

    • Neurospora crassa,
    • nonself recognition,
    • protein targeting,
    • vegetative incompatibility