Increased nuclear traffic chaos in hyphae of Aspergillus nidulans: molecular characterization of apsB and in vivo observation of nuclear behaviour.
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.
Suelmann
R
R
Laboratorium für Mikrobiologie, Philipps-Universität Marburg and Max-Planck-Institut für terrestrische Mikrobiologie, Germany.
Sievers
N
N
Galetzka
D
D
Robertson
L
L
Timberlake
W E
WE
Fischer
R
R
D000595:Amino Acid Sequence; D001233:Aspergillus nidulans / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D001483:Base Sequence; D001692:Biological Transport; D002467:Cell Nucleus / Q000502:physiology*; D003001:Cloning, Molecular; D003593:Cytoplasm / Q000378:metabolism; D004271:DNA, Fungal; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009687:Nuclear Proteins / Q000378:metabolism
C117913:APSB protein, Emericella nidulans; D004271:DNA, Fungal; D005656:Fungal Proteins; D008565:Membrane Proteins; D009687:Nuclear Proteins; C092126:apsA protein, Aspergillus nidulans