Formation and stability of eisosomes in the filamentous fungus Ashbya gossypii.

One hallmark of the rapid expansion of the polar surface of fungal hyphae is the spatial separation of regions of exocytosis and endocytosis at hyphal tips, as recently shown for Ashbya gossypii and Aspergillus nidulans. To determine where cortex-associated eisosomes form with respect to these two regions, we monitored fluorescently marked eisosomes in A. gossypii. Each minute, 1.6 ± 0.5 eisosomes form within the first 30 µm of each hypha and are exclusively subapical of the endocytosis region. This spatial separation of the processes of eisosome formation and endocytosis, and the much lower frequency of eisosome formation compared with that of endocytic vesicle production do not support a recently proposed role for eisosomes in endocytosis. Levels of mRNA encoding eisosome components are tenfold higher in spores than in hyphae, explaining the observed higher eisosome density at the cortex of germ bubbles. As in Saccharomyces cerevisiae, eisosomes in A. gossypii are very stable. In contrast to S. cerevisiae, however, the A. gossypii homologue of Pil1, one of the main eisosome subunits, is very important for polar growth, whereas the homologue of Nce102, which colocalizes with eisosomes, is not needed for eisosome stability. By testing partial deletions of the A. gossypii homologue of Ymr086w, another component of the eisosome, we identified a novel protein domain essential for eisosome stability. We also compare our results with recent findings about eisosomes in A. nidulans.

Ashbya Genome Database 3.0: a cross-species genome and transcriptome browser for yeast biologists.

BACKGROUND: The Ashbya Genome Database (AGD) 3.0 is an innovative cross-species genome and transcriptome browser based on release 40 of the Ensembl developer environment. DESCRIPTION: AGD 3.0 provides information on 4726 protein-encoding loci and 293 non-coding RNA genes present in the genome of the filamentous fungus Ashbya gossypii. A synteny viewer depicts the chromosomal location and orientation of orthologous genes in the budding yeast Saccharomyces cerevisiae. Genome-wide expression profiling data obtained with high-density oligonucleotide microarrays (GeneChips) are available for nearly all currently annotated protein-coding loci in A. gossypii and S. cerevisiae. CONCLUSION: AGD 3.0 hence provides yeast- and genome biologists with comprehensive report pages including reliable DNA annotation, Gene Ontology terms associated with S. cerevisiae orthologues and RNA expression data as well as numerous links to external sources of information. The database is accessible at http://agd.vital-it.ch/.