Suelmann et al. 1998

Nuclear traffic chaos in hyphae of apsB mutants of Aspergillus nidulans: Molecular characterization of apsB and in vivo observations of nuclear behaviour. Mol. Microbiol., 30(4), 831-842.

Suelmann, R., Sievers, N., Galetzka, D., Robertson, L., Timberlake, W.E. & Fischer R.

Abstract

Filamentous fungi are model microorganisms for studying nuclear migration in eukaryotic cells. Two genes, apsA and apsB (=anucleate primary sterigmata), were identified in Aspergillus nidulans that affect nuclear distribution in hyphae and specifically block conidiophore development at the metula stage when mutant. Here we describe the cloning, sequencing and molecular analysis of apsB. The gene encodes a 121 kDa coiled-coil, hydrophilic protein that was localized in the cytoplasm. No protein-protein interaction was detected between ApsB and ApsA, a membrane-associated, previously identified protein. An apsB null mutant was characterized by video epifluorescence microscopy using strains that express green fluorescent protein (GFP) in nuclei. With this novel approach, we have discovered a new mutant phenotype and have found that nuclei display an increased chaotic movement in older hyphal compartments that results in clustering and an uneven distribution of these organelles. These results suggest a regulatory role of ApsB in nuclear migration.