Gene dosage analysis in Azotobacter vinelandii

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Title: Gene dosage analysis in Azotobacter vinelandii
Authors: Maldonado, Rafael | Garzón Villar, Andrés | Dean, Dennis R. | Casadesús Pursals, Josep
Research Group/s: Transducción de Señales en Bacterias
Center, Department or Service: Universidad de Alicante. Departamento de Fisiología, Genética y Microbiología | Universidad de Sevilla. Departamento de Genética | Virginia State University. Department ofAnaerobic Microbiology
Keywords: Polyploidy | Chromosome
Knowledge Area: Genética | Microbiología
Issue Date: Dec-1992
Publisher: Genetics Society of America
Citation: MALDONADO CARO, Rafael Diego, et al. “Gene dosage analysis in Azotobacter vinelandii”. Genetics. Vol. 132 (Dec. 1992). ISSN 0016-6731, pp. 869-878
Abstract: For more than a decade, Azotobacter vinelandii has been considered a polyploid bacterium on the basis of physical studies of chromosome size and DNA content per cell. However, as described in the present work, many genetic operations can be performed in A. vinelandii without the constraints expected in a polyploid bacterium: (i) reversion of transposon-induced mutations is usually associated with loss of the transposable element; (ii) revertants retaining the transposon always carry secondary transpositions; (iii) heterozygotic transconjugants and transformants are unstable and segregate homozygotic colonies even in the absence of selection. Physical monitoring of segregation, achieved by colony hybridization, indicates that phenotypic expression of an allele is always correlated with its physical presence, thus ruling out the existence of either threshold dosage requirements or transcriptionally inactive DNA. Chromosomal lac fusions constructed by double crossover with a linearized plasmid show a segregation pattern consistent with the inheritance of one or several chromosomes per daughter cell. Analysis of the delay required for the expression of recessive chromosomal mutations such as rif, nal and str provides further evidence that A. vinelandii is not a polyploid bacterium.
Sponsor: This work was supported by grant PB89-0627 from the Dirección General de Ivestigación Científica y Técnica, Spain (to J.C.) and by grant DMB-8917371 from the National Science Foundation (to D.R.D.).
ISSN: 0016-6731 (Print) | 1943-2631 (Online)
Language: eng
Type: info:eu-repo/semantics/article
Rights: Copyright © 1992 by the Genetics Society of America
Peer Review: si
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