Ribosomal DNA is a site of chromosome breakage in aneuploid strains of Neurospora
Article Abstract:
A translocation strain of Neurospora crassa, termed T(I;V)AR 190, was constructed by moving most of the right arm of linkage group (LG) I to the distal tip of the nucleolus organizer region (NOR), while rDNA repeat units were moved to the truncated region in LG I. In partial diploids derived from T(I;V)AR 190, frequent chromosomal breakages were obsereved in the NOR, at sites heterogeneous with respect to their position in the rDNA repeat unit. The resulting rDNA exposed by the breakages could be 'healed' by the annealment of new telomeres. These results imply that in eukaryotic chromosomes, rDNA sites can be prone to breakage.
Publication Name: Genetics
Subject: Biological sciences
ISSN: 0016-6731
Year: 1992
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Use of gene replacement transformation to elucidate gene function in the qa gene cluster of Neurospora crassa
Article Abstract:
Gene replacement was used to study the function of the qa-x, qa-y and qa-1S genes of Neurospora crassa. The qa-y gene coded for a quinic acid permease which is essential in the uptake of quinic acid. The qa-1S gene product seems to be a repressor molecule that could be involved in catabolite repression of the qa gene cluster. Transcription of several qa genes in strains with the qa-1S deletion in the presence of glucose suggest a mechanism of repression that does not involve upstream inhibitors or inhibition of activator binding. However, the role of the qa-x gene in quinic acid metabolism could not be defined.
Publication Name: Genetics
Subject: Biological sciences
ISSN: 0016-6731
Year: 1992
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A combination inversion and translocation in Neurospora crassa with inviable deficiency progeny that can be rescued in heterokaryons
Article Abstract:
Inversion and translocation in the IL, IR and IIIR genes in Neurospora crassa were studied to analyze the cytogenetics of this complex rearrangement of genes. A progeny containing one of the products of meiotic segregation contained a genome that is duplicated or partially deficient. This progeny was viable only until acrospore germination. The defective progeny can be saved by fusion with an appropriate mutant auxotroph forming a heterokaryon.
Publication Name: Genetics
Subject: Biological sciences
ISSN: 0016-6731
Year: 1992
User Contributions:
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