Bacterial Systems for Testing Spontaneous and Induced Mutations

Abstract The suppressor of Hairy-wing [su(Hw)] protein mediates the mutagenic effect of the gypsy retrotransposon by repressing the function of transcriptional enhancers located distally from the promoter with respect to the position of the su(Hw)-binding region. Mutations in a second gene, modifier of mdg4, also affect the gypsy-induced phenotype. Two major effects of the mod(mdg4)lul mutation can be distinguished: the interference with insulation by the su(Hw)-binding region and direct inhibition of gene expression that is not dependent on the su(Hw)-binding region position. The mod(mdg4)lul mutation partially suppresses ct6, scD1 and Hw1 mutations, possibly by interfering with the insulation effect of the su(Hw)-binding region. An example of the second effect of mod(mdg4)lul is a complete inactivation of yellow expression in combination with the y 2 allele. Phenotypic analyses of flies with combinations of mod(mdg4)lul and different su(Hw) mutations, or with constructions carrying deletions of the acidic domains of the su(Hw) protein, suggest that the carboxy-terminal acidic domain is important for direct inhibition of yellow transcription in bristles, while the amino-terminal acidic domain is more essential for insulation.

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MOLECULAR GENETIC ANALYSIS OF THE DILUTE-SHORT EAR (d-se) REGION OF THE MOUSE

Genetics ◽

10.1093/genetics/112.2.321 ◽

1986 ◽

Vol 112 (2) ◽

pp. 321-342

Author(s):

Eugene M Rinchik ◽

Liane B Russell ◽

Neal G Copeland ◽

Nancy A Jenkins

Keyword(s):

Physical Map ◽

Leukemia Virus ◽

Molecular Genetic ◽

Break Point ◽

Virus Genome ◽

Molecular Genetic Analysis ◽

Chromosome 9 ◽

Genetic Complementation ◽

Induced Mutations ◽

Radiation Induced

ABSTRACT Genes of the dilute-short ear (d-se) region of mouse chromosome 9 comprise an array of loci important to the normal development of the animal. Over 200 spontaneous, chemically induced and radiation-induced mutations at these loci have been identified, making it one of the most genetically well-characterized regions of the mouse. Molecular analysis of this region has recently become feasible by the identification of a dilute mutation that was induced by integration of an ecotropic murine leukemia virus genome. Several unique sequence cellular DNA probes flanking this provirus have now been identified and used to investigate the organization of wild-type chromosomes and chromosomes with radiation-induced d-se region mutations. As expected, several of these mutations are associated with deletions, and, in general, the molecular and genetic complementation maps of these mutants are concordant. Furthermore, a deletion break-point fusion fragment has been identified and has been used to orient the physical map of the d-se region with respect to the genetic complementation map. These experiments provide important initial steps for analyzing this developmentally important region at the molecular level, as well as for studying in detail how a diverse group of mutagens acts on the mammalian germline.

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GENETIC MAPPING OF GENES REQUIRED FOR MOTILITY IN CAULOBACTER CRESCENTUS

Genetics ◽

10.1093/genetics/108.3.523 ◽

1984 ◽

Vol 108 (3) ◽

pp. 523-532

Author(s):

Bert Ely ◽

Ronda H Croft ◽

Connie J Gerardot

Keyword(s):

Genetic Mapping ◽

Caulobacter Crescentus ◽

Pleiotropic Effect ◽

Structure And Function ◽

Bacteriophage Resistance ◽

And Function ◽

Chromosomal Map ◽

Bacterial Systems

ABSTRACT Mutations in more than 30 genes affect motility in Caulobacter crescentus. We have determined the chromosomal map locations for 27 genes involved in flagellar morphogenesis (fla), three genes involved in flagellar function (mot), and three genes that have a pleiotropic effect on both motility and bacteriophage resistance (ple). Three multigene clusters have been detected at widely separated chromosomal locations, but in addition, there are 12 fla and mot genes that are found at eight additional sites scattered around the C. cresentus chromosome. Thus, there is more scatter of genes involved in flagellar structure and function than has been observed in other bacterial systems.

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Whole-Genome Effects of Ethyl Methanesulfonate-Induced Mutation on Nine Quantitative Traits in Outbred Drosophila melanogaster

Genetics ◽

10.1093/genetics/157.3.1257 ◽

2001 ◽

Vol 157 (3) ◽

pp. 1257-1265 ◽

Cited By ~ 3

Author(s):

Hsiao-Pei Yang ◽

Ana Y Tanikawa ◽

Wayne A Van Voorhies ◽

Joana C Silva ◽

Alexey S Kondrashov

Keyword(s):

Drosophila Melanogaster ◽

Quantitative Traits ◽

Spontaneous Mutation ◽

Developmental Time ◽

Ethyl Methanesulfonate ◽

Induced Mutations ◽

Mean Values ◽

Eye Color ◽

Recessive Mutations ◽

The Mean

Abstract We induced mutations in Drosophila melanogaster males by treating them with 21.2 mm ethyl methanesulfonate (EMS). Nine quantitative traits (developmental time, viability, fecundity, longevity, metabolic rate, motility, body weight, and abdominal and sternopleural bristle numbers) were measured in outbred heterozygous F3 (viability) or F2 (all other traits) offspring from the treated males. The mean values of the first four traits, which are all directly related to the life history, were substantially affected by EMS mutagenesis: the developmental time increased while viability, fecundity, and longevity declined. In contrast, the mean values of the other five traits were not significantly affected. Rates of recessive X-linked lethals and of recessive mutations at several loci affecting eye color imply that our EMS treatment was equivalent to ∼100 generations of spontaneous mutation. If so, our data imply that one generation of spontaneous mutation increases the developmental time by 0.09% at 20° and by 0.04% at 25°, and reduces viability under harsh conditions, fecundity, and longevity by 1.35, 0.21, and 0.08%, respectively. Comparison of flies with none, one, and two grandfathers (or greatgrandfathers, in the case of viability) treated with EMS did not reveal any significant epistasis among the induced mutations.

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Mutator-Induced Mutations of the rf1 Nuclear Fertility Restorer of T-Cytoplasm Maize Alter the Accumulation of T-urfl3 Mitochondrial Transcripts

Genetics ◽

10.1093/genetics/143.3.1383 ◽

1996 ◽

Vol 143 (3) ◽

pp. 1383-1394

Author(s):

Roger P Wise ◽

Carren L Dill ◽

Patrick S Schnable

Keyword(s):

Pollen Fertility ◽

Fertility Restoration ◽

Mitochondrial Rna ◽

Induced Mutations ◽

Male Sterile ◽

Fertility Restorer ◽

Restorer Genes ◽

Mitochondrial Transcripts ◽

Ecori Restriction ◽

Fertility Restorer Genes

Abstract Dominant alleles of the rf1 and rf2 nuclear-encoded fertility restorer genes are necessary for restoration of pollen fertility in T-cytoplasm maize. To further characterize fertility restoration mediated by the Rf1 allele, 123,500 gametes derived from plants carrying the Mutator transposable element family were screened for rf1-mutant alleles (rf1-m) Four heritable rf1-m alleles were recovered from these populations. Three rf1-m alleles were derived from the progenitor allele Rf1-IAl53 and one was derived from Rf1-Ky21. Cosegregation analysis revealed 5.5- and 2.4kb Mu1-hybridizing EcoRI restriction fragments in all of the male-sterile and none of the male-fertile plants in families segregating for rf1-m3207 and rf1-m3310, respectively. Mitochondrial RNA gel blot analyses indicated that all four rf1-m alleles in male-sterile plants cosegregated with the altered steady-state accumulation of 1.6 and O.6-kb T-urf13 transcripts, demonstrating that these transcripts are Rf1 dependent. Plants carrying a leaky mutant, rf1-m7323, revealed variable levels of Rf1-associated, T-urf13 transcripts and the degree of pollen fertility. The ability to obtain rf1-m derivatives from Rf1 indicates that Rf1 alleles produce a functional gene product necessary for the accumulation of specific T-urf13 transcripts in T-cytoplasm maize.

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