Polarity of meiotic gene conversion is 5′ to 3′ within the niaD gene of Aspergillus nidulans

Thijs, H.; Garde, Julie; Goosen, T.; Tomsett, Brian; Swart, K.; Heyting, C.; Broek, H.W.J. van den

doi:10.1007/bf00293202

Cited by 7 publications

(2 citation statements)

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“…Therefore, geneticists studying recombination in organisms where tetrad analysis is not possible have tended to refer to IGRs bearing a parental or noncrossover (NCO) arrangement of flanking markers as convertants, a convention that we also follow in this paper. In these cases, a convenient way of detecting conversion polarity is to compare the relative frequencies with which the two parentally marked IGRs are recovered from heteroallelic combinations (5,16).…”

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confidence: 99%

Polarized gene conversion at the bz locus of maize

Dooner

2014

Proc. Natl. Acad. Sci. U.S.A.

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Nucleotide diversity is greater in maize than in most organisms studied to date, so allelic pairs in a hybrid tend to be highly polymorphic. Most recombination events between such pairs of maize polymorphic alleles are crossovers. However, intragenic recombination events not associated with flanking marker exchange, corresponding to noncrossover gene conversions, predominate between alleles derived from the same progenitor. In these dimorphic heterozygotes, the two alleles differ only at the two mutant sites between which recombination is being measured. To investigate whether gene conversion at the bz locus is polarized, two large diallel crossing matrices involving mutant sites spread across the bz gene were performed and more than 2,500 intragenic recombinants were scored. In both diallels, around 90% of recombinants could be accounted for by gene conversion. Furthermore, conversion exhibited a striking polarity, with sites located within 150 bp of the start and stop codons converting more frequently than sites located in the middle of the gene. The implications of these findings are discussed with reference to recent data from genome-wide studies in other plants.meiotic recombination | conversion polarity

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confidence: 99%

Polarized gene conversion at the bz locus of maize

Dooner

2014

Proc. Natl. Acad. Sci. U.S.A.

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“…Isolation of DNA and RNA Small-scale DNA isolations from fungal mycelium for Southern hybridization and PCR were carried out as described previously (Thijs et al 1995). For RNA isolations 1±2 g of frozen, ground mycelium was homogenized in 33 ml of denaturation buer (42 mM sodium citrate pH 4.0, 0.83% N-lauryl sarcosinate, 0.2 mM b-mercaptoethanol).…”

Section: Transformation Of a Nidulansmentioning

confidence: 99%

Cloning, sequencing, disruption and phenotypic analysis of uvsC, an Aspergillus nidulans homologue of yeast RAD51

et al. 1997

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We have cloned the uvsC gene of Aspergillus nidulans by complementation of the A. nidulans uvsC114 mutant. The predicted protein UVSC shows 67.4% sequence identity to the Saccharomyces cerevisiae Rad51 protein and 27.4% sequence identity to the Escherichia coli RecA protein. Transcription of uvsC is induced by methyl-methane sulphonate (MMS), as is transcription of RAD51 of yeast. Similar levels of uvsC transcription were observed after MMS induction in a uvsC+ strain and the uvsC114 mutant. The coding sequence of the uvsC114 allele has a deletion of 6 bp, which results in deletion of two amino acids and replacement of one amino acid in the translation product. In order to gain more insight into the biological function of the uvsC gene, a uvsC null mutant was constructed, in which the entire uvsC coding sequence was replaced by a selectable marker gene. Meiotic and mitotic phenotypes of a uvsC+ strain, the uvsC114 mutant and the uvsC null mutant were compared. The uvsC null mutant was more sensitive to both UV and MMS than the uvsC114 mutant. The uvsC114 mutant arrested in meiotic prophase-I. The uvsC null mutant arrested at an earlier stage, before the onset of meiosis. One possible interpretation of these meiotic phenotypes is that the A. nidulans homologue of Rad51 of yeast has a role both in the specialized processes preceding meiosis and in meiotic prophase I.

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