title: Translocations used to generate chromosome segment duplications in Neurospora can disrupt genes and create novel open reading frames.
abstract: In Neurospora crassa, crosses between normal sequence strains and strains bearing some translocations can yield progeny bearing a duplication (Dp) of the translocated chromosome segment. Here, 30 breakpoint junction sequences of 12 Dp-generating translocations were determined. The breakpoints disrupted 13 genes (including predicted genes), and created 10 novel open reading frames. Insertion of sequences from LG III into LG I as translocation T(UK8-18) disrupts the eat-3 gene, which is the ortholog of the Podospora anserine gene ami1. Since ami1-homozygous Podospora crosses were reported to increase the frequency of repeat-induced point mutation (RIP), we performed crosses homozygous for a deficiency in eat-3 to test for a corresponding increase in RIP frequency. However, our results suggested that, unlike in Podospora, the eat-3 gene might be essential for ascus development in Neurospora. Duplication-heterozygous crosses are generally barren in Neurospora; however, by using molecular probes developed in this study, we could identify Dp segregants from two different translocation-heterozygous crosses, and using these we found that the barren phenotype of at least some duplication-heterozygous crosses was incompletely penetrant.
authors.affiliation: Centre for Cellular and Molecular Biology, Hyderabad 500 007, India.
authors.forename: Parmit K
authors.initials: PK
authors.lastname: Singh
authors.forename: Srividhya V
authors.initials: SV
authors.lastname: Iyer
authors.forename: T Naga
authors.initials: TN
authors.lastname: Sowjanya
authors.forename: B Kranthi
authors.initials: BK
authors.lastname: Raj
authors.forename: Durgadas P
authors.initials: DP
authors.lastname: Kasbekar
mesh_terms: D056905:Chromosome Breakpoints; D058674:Chromosome Duplication; D015825:Chromosomes, Fungal / Q000235:genetics*; D017353:Gene Deletion; D005800:Genes, Fungal; D005819:Genetic Markers; D006824:Hybridization, Genetic; D009492:Neurospora crassa / Q000235:genetics*; D016366:Open Reading Frames; D010641:Phenotype; D014178:Translocation, Genetic
chemical_list: D005819:Genetic Markers