Increased nuclear traffic chaos in hyphae of Aspergillus nidulans: molecular characterization of apsB and in vivo observation of nuclear behaviour

Suelmann, Rüdiger; Sievers, Nicole; Galetzka, Danuta; Robertson, Laura S.; Timberlake, William E.; Fischer, Reinhard

doi:10.1046/j.1365-2958.1998.01115.x

Cited by 38 publications

(36 citation statements)

References 40 publications

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“…Moreover, since ApsB localizes to septa, it could tether MTs and attached nuclei to septa. Indeed, previous studies showed that nuclei move more freely along the hyphae in apsB mutants (Suelmann et al, 1998) (see supplementary material Movies 2 and 3).…”

Section: Discussionmentioning

confidence: 79%

“…ApsB is a novel spindle-pole body (SPB) associated protein AspB was described as a cytoplasmic protein with a spot-like distribution when expressed at high levels under the control of the inducible alcA-promoter (Suelmann et al, 1998). We reinvestigated the distribution of ApsB at lower expression levels and compared the localization pattern of C-terminally tagged ApsB-GFP with a homologously integrated construct in which ApsB was tagged with GFP at the N-terminus (GFP-ApsB).…”

Section: Mutation Of Apsa and Apsb Affect Mt Organizationmentioning

confidence: 99%

“…The apsA gene encodes a 186 kDa coiledcoil protein with similarity to the cortical Num1 protein of S. cerevisiae, whereas ApsB is a 121 kDa coiled-coil protein and was originally localized as spots in the cytoplasm (Suelmann et al, 1998). Both aps mutants were long known to have nuclear migration defects (see supplementary material, Movies 1-5), but the reason was unclear (Fischer and Timberlake, 1995;Suelmann et al, 1997;Suelmann et al, 1998). In this paper, we show that the apsA and the apsB mutations have effects on the MT cytoskeleton and describe ApsB as a novel spindle-pole body associated protein.…”

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confidence: 99%

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Role of the spindle-pole-body protein ApsB and the cortex protein ApsA in microtubule organization and nuclear migration in Aspergillus nidulans

Veith

Scherr

Efimov

et al. 2005

Journal of Cell Science

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Nuclear migration and positioning in Aspergillus nidulans depend on microtubules, the microtubule-dependent motor protein dynein, and auxiliary proteins, two of which are ApsA and ApsB. In apsA and apsB mutants nuclei are clustered and show various kinds of nuclear navigation defects, although nuclear migration itself is still possible. We studied the role of several components involved in nuclear migration through in vivo fluorescence microscopy using fluorescent-protein tagging. Because ApsA localizes to the cell cortex and mitotic spindles were immobile in apsA mutants, we suggest that astral microtubule-cortex interactions are necessary for oscillation and movement of mitotic spindles along hyphae, but not for post-mitotic nuclear migration. Mutation of apsA resulted in longer and curved microtubules and displayed synthetic lethality in combination with the conventional kinesin mutation ΔkinA. By contrast, ApsB localized to spindle-pole bodies (the fungal centrosome), to septa and to spots moving rapidly along microtubules. The number of cytoplasmic microtubules was reduced in apsB mutants in comparison to the wild type, indicating that cytoplasmic microtubule nucleation was affected, whereas mitotic spindle formation appeared normal. Mutation of apsB suppressed dynein null mutants, whereas apsA mutation had no effect. We suggest that nuclear positioning defects in the apsA and apsB mutants are due to different effects on microtbule organisation. A model of spindle-pole body led nuclear migration and the roles of dynein and microtubules are discussed.

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Section: Discussionmentioning

confidence: 79%

Section: Mutation Of Apsa and Apsb Affect Mt Organizationmentioning

confidence: 99%

mentioning

confidence: 99%

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Role of the spindle-pole-body protein ApsB and the cortex protein ApsA in microtubule organization and nuclear migration in Aspergillus nidulans

Veith

Scherr

Efimov

et al. 2005

Journal of Cell Science

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“…Optically sectioned nuclei in the early stages of mitosis revealed previously undescribed chromosomal behaviors (22), and epifluorescence video microscopy facilitated identification of new mutant phenotypes and, ultimately, the genes affecting nuclear migration (see the video at http://www.blacksci.co.uk/products/journals/molextra.htm.) (57,58).…”

Section: Investigating Cell Dynamics With Gfpmentioning

confidence: 99%

Green Fluorescent Protein Is Lighting Up Fungal Biology

Lorang

Tuori

Martinez

et al. 2001

Appl Environ Microbiol

280

202

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4Prasher (42) cloned a cDNA for the green fluorescent protein (GFP) gene from the jellyfish Aequorea victoria in 1992. Shortly thereafter, to the amazement of many investigators, this gene or derivatives thereof were successfully expressed and conferred fluorescence to bacteria and Caenorhabditis elegans cells in culture (10, 31), followed by yeast (24,39), mammals (40), Drosophila (66), Dictyostelium (23,30), plants (28,49), and filamentous fungi (54). The tremendous success of GFP as a reporter can be attributed to unique qualities of this 238-amino-acid, 27-kDa protein which absorbs light at maxima of 395 and 475 nm and emits light at a maximum of 508 nm. The fluorescence of GFP requires only UV or blue light and oxygen, and therefore, unlike the case with other reporters (␤-glucuronidase, ␤-galacturonidase, chloramphenicol acetyltransferase, and firefly luciferase) that rely on cofactors or substrates for activity, in vivo observation of gfp expression is possible with individual cells, with cell populations, or in whole organisms interacting with symbionts or environments in real time. Complications caused by destructive sampling, cell permeablization for substrates, or leakage of products do not occur. Furthermore, the GFP protein is extremely stable in vivo and has been fused to the C or N terminus of many cellular and extracellular proteins without a loss of activity, thereby permitting the tagging of proteins for gene regulation analysis, protein localization, or specific organelle labeling. The mature protein resists many proteases and is stable up to 65°C and at pH 5 to 11, in 1% sodium dodecyl sulfate or 6 M guanidinium chloride (reviewed in references 17 and 67), and in tissue fixed with formaldehyde, methanol, or glutaraldehyde. However, GFP loses fluorescence in methanol-acetic acid (3:1) and can be masked by autofluorescent aldehyde groups in tissue fixed with glutaraldehyde. Fluorescence is optimal at pH 7.2 to 8.0 (67).Limitations on GFP as a reporter for some applications are its low turnover rate, 2-h lag time for autoactivation of its chromophore, improper folding at high temperatures (37°C), which results in nonfluorescent and insoluble forms of the protein, and requirement for oxygen, which is not present in equal concentrations in all subcellular locations or cell types (reviewed in references 17 and 67). These characteristics of GFP, however, have not posed a problem for many applications, and mutant forms of GFP that have an ability to fold properly at high temperatures, increased solubility and fluorescence, reduced photobleaching (16, 17, 51), and reduced half-lives (1) have been developed. Coupled with fluorescenceactivated cell sorting, confocal microscopy or quantitative image analysis techniques, GFP technology can be used to isolate transformed cells or specific cell types from populations of cells (14), to quantify gene expression of individual cells within whole organisms (8), or to assess the dispersal and biomass of organisms in complex environments, such as in animal or plan...

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“…fungi because interphase nuclei migrate within the hyphae (Suelmann et al, 1998). Nevertheless, the dynamic behavior of Kar9 appears to be conserved in MigA.…”

Section: Discussionmentioning

confidence: 99%

Genetic evidence for a microtubule-capture mechanism during polar growth of Aspergillus nidulans

Manck

Ishitsuka

Herrero

et al. 2015

Journal of Cell Science

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The cellular switch from symmetry to polarity in eukaryotes depends on the microtubule (MT) and actin cytoskeletons. In fungi such as Schizosaccharomyces pombe or Aspergillus nidulans, the MT cytoskeleton determines the sites of actin polymerization through cortical cell-end marker proteins. Here we describe A. nidulans MT guidance protein A (MigA) as the first ortholog of the karyogamy protein Kar9 from Saccharomyces cerevisiae in filamentous fungi. A. nidulans MigA interacts with the cortical ApsA protein and is involved in spindle positioning during mitosis. MigA is also associated with septal and nuclear MT organizing centers (MTOCs). Superresolution photoactivated localization microscopy (PALM) analyses revealed that MigA is recruited to assembling and retracting MT plus ends in an EbA-dependent manner. MigA is required for MT convergence in hyphal tips and plays a role in correct localization of the cell-end markers TeaA and TeaR. In addition, MigA interacts with a class-V myosin, suggesting that an active mechanism exists to capture MTs and to pull the ends along actin filaments. Hence, the organization of MTs and actin depend on each other, and positive feedback loops ensure robust polar growth.

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Increased nuclear traffic chaos in hyphae of Aspergillus nidulans: molecular characterization of apsB and in vivo observation of nuclear behaviour

Cited by 38 publications

References 40 publications

Role of the spindle-pole-body protein ApsB and the cortex protein ApsA in microtubule organization and nuclear migration in Aspergillus nidulans

Role of the spindle-pole-body protein ApsB and the cortex protein ApsA in microtubule organization and nuclear migration in Aspergillus nidulans

Green Fluorescent Protein Is Lighting Up Fungal Biology

Genetic evidence for a microtubule-capture mechanism during polar growth of Aspergillus nidulans

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