• Animal cells and systems
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• v.2 no.1
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• pp.123-131
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• 1998

The unc-29 region on the chromosome I of Caenorhabditis elegans has been mutagenized in order to obtain lethal mutations. In this screen, the uncoordinated phenotype of unc-29 (e193) mutant was used to identify any lethal mutations closely linked to the unc-29 gene, which encodes a subunit of nicotinic acetylcholine receptors. We have isolated six independent mutations (jh1 to jh6) out of approximately 5,200 ethyl methanesulfonate(EMS) treated haploids. Four of the six mutations demonstrated embryonic lethal phenotypes, while the other two showed embryonic and larval lethal phenotypes. Terminal phenotypes observed in two mutations (jh1 and jh2) indicated developmental defects specific to posterior part of embryos which appeared similar to the phenotypes observed in nob (no back end) mutants. Another mutation (jh4) resulted in an interesting phenotype of body-wall muscle degeneration at larval stage. These mutations were mapped by using three-factor crosses and deficiency mutants in this region. Here we report genetic analysis and characterization of these lethal mutations.

• Journal of Microbiology
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• v.41 no.2
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• pp.115-120
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• 2003

Mex67p/Tap are evolutionally conserved mRNA export factors. To identify mutations in genes that are functionally linked to mex67 with respect to mRNA export, we used a synthetic lethal genetic screen in Schizosaccharomyces pombe. Three synthetic lethal mutants were isolated and mutations in these mutants defined separate complementation groups. These mutants exhibited the accumulation of poly A$\^$+/ RNA in the nucleus, with a decrease in the cytoplasm under synthetically lethal conditions, suggesting that the mutations cause an mRNA nuclear export defect. In addition, the S. pombe genes that were found to be involved in mRNA export did not suppress the synthetic lethality of these mutants. These results indicate that the isolated mutants contain mutations in new genes, which are involved in mRNA export from the nucleus.

• Journal of Environmental Science International
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• v.4 no.5
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• pp.157-157
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• 1995

In order to analyze the sex-linked lethal mutagenic effects of ethyl methanesulfonate (EMS) in Drosophila melanogaster, the mutagenicities from the attached-X and Basc method have been detected. The indexes of relative lethal mutations at 2.0 and 4.0mM EMS treated group using the attached-X method were about 1.5 and 2.4 times than that of 1.0mM treated group, respectively. EMS had more pronounced effect in the sperm and spermatid stages in the induction of X-linked lethal mutations during the spermatogenesis. And, in the induction of X-linked recessive lethal mutations from the Basc method, the mutation frequency of 4.0mM EMS treated group as compared with 2.0mM was more than three fold. Two assay systems used in this study can support mutually according to experimental purposes, and the area of its application can be considerably wide.

• Journal of Environmental Science International
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• v.4 no.5
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• pp.543-549
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• 1995

In order to analyze the sex-linked lethal mutagenic effects of ethyl methanesulfonate (EMS) in Drosophila melanogaster, the mutagenicities from the attached-X and Basc method have been detected. The indexes of relative lethal mutations at 2.0 and 4.0mM EMS treated group using the attached-X method were about 1.5 and 2.4 times than that of 1.0mM treated group, respectively. EMS had more pronounced effect in the sperm and spermatid stages in the induction of X-linked lethal mutations during the spermatogenesis. And, in the induction of X-linked recessive lethal mutations from the Basc method, the mutation frequency of 4.0mM EMS treated group as compared with 2.0mM was more than three fold. Two assay systems used in this study can support mutually according to experimental purposes, and the area of its application can be considerably wide.

• The Korean Journal of Zoology
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• v.8 no.2
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• pp.33-36
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• 1965

We have carried out a study on the modification of the frequency of X-ray induced lethal and slow growing mutations by colchincine treatment before and after X-ray irradiation in Paramecium aurelia. 1. Lethal and slow-growing mutation induced by X-ray in Paramecium aurelia were reduced by colchicine treatment. 2. The effects of colchicine on the X-ray induced mutations were remarkable in the radiosensitive stages of cell division. 3. The pre-irradiation treatment with colchicine showed no significant influence on the frequency of mutations. 4. It is believed that the reduction of mutation induced by X-ray after treatment with colchicine was due to the fact that the delay of the cell division allowed more time for the pre-mutational damage to recover.

• Archives of Pharmacal Research
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• v.22 no.3
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• pp.229-231
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• 1999

Recessive oncogenes are genetic functions important in the regulation of tissue growth and differentiation. These genetic functions are defined on the basis of the phenotype expressed by homozygotes. Defining the role of these genes in normal developmental and physiological processes is important to the development of accurate models of the normal regulation of growth and differentiation. Drosophila can be a good system to investigate the neoplastic mechanism of oncogenes and provide a greater understanding in the developmental progression of both invertebrates and vertebrates and vertebrates. The lethal (2) giant larvae gene is a recessive oncogene of Drosophila and temperature sensitive mutations of this gene have been isolated. Here, the application of temperature-sensitive mutations in Drosophila oncogene studies is discussed.

• ALGAE
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• v.34 no.1
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• pp.35-43
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• 2019

Genetic study of haploid organisms offers the advantage that mutant phenotypes are directly displayed, but has the disadvantage that strains carrying lethal mutations are not readily maintained. We describe an approach for generating and performing genetic analysis of diploid strains of Chlamydomonas reinhardtii, which is normally haploid. First protocol utilizes self-mating diploid strains that will facilitate the genetic analysis of recessive lethal mutations by offering a convenient way to produce homozygous diploids in a single mating. Second protocol is designed to reduce the chance of contamination and the accumulation of spontaneous mutations for long-term storage of mutant strains. Third protocol for inducing the meiotic program is also included to produce haploid mutant strains following tetraploid genetic analysis. We discuss implication of self-fertile strains for the future of Chlamydomonas research.

• Journal of Ginseng Research
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• v.45 no.1
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• pp.149-155
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• 2021

Background: We have reported that internal deletions in the nef, gag, and pol genes in HIV-1-infected patients are induced in those treated with Korean Red Ginseng (KRG). KRG delays the development of resistance mutations to antiretroviral drugs. Methods: The vif-vpr genes over 26 years in 20 hemophiliacs infected with HIV-1 from a single source were sequenced to investigate whether vif-vpr genes were affected by KRG and KRG plus highly active antiretroviral therapy (ART) (hereafter called GCT) and compared the results with our previous data. Results: A significantly higher number of in-frame small deletions were found in the vif-vpr genes of KRG-treated patients than at the baseline, in control patients, and in ART-alone patients (p < 0.001). These were significantly reduced in GCT patients (p < 0.05). In contrast, sequences harboring a premature stop codon (SC) were more significant in GCT patients (10.1%) than in KRG-alone patients, control (p < 0.01), and ART-alone patients (p = 0.078 for peripheral blood mononuclear cells). The proportion of SC in Vpr was similar to that in Vif, whereas the proportion of sequences revealing SC in the env-nef genes was significantly lower than that in the pol-vif-vpr genes (p < 0.01). The genetic distance was 1.8 times higher in the sequences harboring SC than in the sequences without SC (p < 0.001). Q135P in the vif gene is significantly associated with rapid progression to AIDS (p < 0.01). Conclusion: Our data show that KRG might induce sD in the vif-vpr genes and that vif-vpr genes are similarly affected by lethal mutations.

• Journal of Microbiology
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• v.42 no.1
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• pp.32-36
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• 2004

We have previously isolated three synthetic lethal mutants from Schizosaccharomyces pombe in order to identify mutations in the genes that are functionally linked to spmex67 with respect to mRNA export. A novel rsm1 gene was isolated by complementation of the growth defect in one of the synthetic lethal mutants, SLMex1. The rsml gene contains no introns and encodes a 296 amino-add-long protein with the RING finger domain, a C3HC4 in the N-terminal half. The Δrsm1 null mutant is viable, but it showed a slight poly(A)$\^$＋/ RNA accumulation in the nucleus. Also, the combination of Δrsm1 and Δspmex67 mutations confers synthetic lethality that is accompanied by the severe poly(A)$\^$＋/ RNA export defect. These results suggest that rsm1 is involved in mRNA export from the nucleus.

• Proceedings of the Zoological Society Korea Conference
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• 1997.10b
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• pp.259.1-259
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• 1997

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