title: Telomere position effect is regulated by heterochromatin-associated proteins and NkuA in Aspergillus nidulans.
abstract: Gene-silencing mechanisms are being shown to be associated with an increasing number of fungal developmental processes. Telomere position effect (TPE) is a eukaryotic phenomenon resulting in gene repression in areas immediately adjacent to telomere caps. Here, TPE is shown to regulate expression of transgenes on the left arm of chromosome III and the right arm of chromosome VI in Aspergillus nidulans. Phenotypes found to be associated with transgene repression included reduction in radial growth and the absence of sexual spores; however, these pleiotropic phenotypes were remedied when cultures were grown on media with appropriate supplementation. Simple radial growth and ascosporogenesis assays provided insights into the mechanism of TPE, including a means to determine its extent. These experiments revealed that the KU70 homologue (NkuA) and the heterochromatin-associated proteins HepA, ClrD and HdaA were partially required for transgene silencing. This study indicates that TPE extends at least 30&emsp14;kb on chromosome III, suggesting that this phenomenon may be important for gene regulation in subtelomeric regions of A. nidulans.
authors: Department of Plant Pathology, University of Wisconsin, Madison, WI 53706, USA.
authors: Jonathan M
authors: JM
authors: Palmer
authors: Department of Biology, University of Kentucky, Lexington, KY 40506, USA.
authors: Sandeep
authors: S
authors: Mallaredy
authors: Department of Biology, University of Kentucky, Lexington, KY 40506, USA.
authors: Dustin W
authors: DW
authors: Perry
authors: School of Pharmacy, University of Southern California, Los Angeles, CA 90089-9023, USA.
authors: James F
authors: JF
authors: Sanchez
authors: Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI 53706, USA.
authors: Jeffrey M
authors: JM
authors: Theisen
authors: Department of Molecular Genetics, Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA.
authors: Edyta
authors: E
authors: Szewczyk
authors: Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045, USA.|Department of Molecular Genetics, Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA.
authors: Berl R
authors: BR
authors: Oakley
authors: School of Pharmacy, University of Southern California, Los Angeles, CA 90089-9023, USA.
authors: Clay C C
authors: CCC
authors: Wang
authors: Department of Bacteriology, University of Wisconsin, Madison, WI 53706, USA.|Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI 53706, USA.
authors: Nancy P
authors: NP
authors: Keller
authors: Department of Biology, University of Kentucky, Lexington, KY 40506, USA.
authors: Peter M
authors: PM
authors: Mirabito
mesh_terms: D034961:Antigens, Nuclear / Q000235:genetics / Q000378:metabolism*; D001233:Aspergillus nidulans / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D020868:Gene Silencing; D006570:Heterochromatin / Q000235:genetics / Q000378:metabolism*; D000072200:Ku Autoantigen; D016615:Telomere / Q000235:genetics / Q000378:metabolism*
chemical_list: D034961:Antigens, Nuclear; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D006570:Heterochromatin; D000072200:Ku Autoantigen