Finished Department of Soil Microbiology, Soil Science Faculty, Moscow State University, Moscow, Russia. 1st Ph.D. - Gamaleya Research Institute of Epidemiology and Microbiology, Moscow Russia. 2nd Ph. D. - Univerrsitee de l Mediterranee, Marseille, France.Present place of work - University of Rochester, Rochester, NY, USA
It has been independently demonstrated by us1 and Liang et al.2 that naked mole-rat (NMR) cells a... more It has been independently demonstrated by us1 and Liang et al.2 that naked mole-rat (NMR) cells are more resistant to SV40LT and H-RasV12-induced transformation than mouse cells. In the accompanying comment, Hadi et al. argued that NMR cells and mouse cells are equally susceptible to oncogenic transformation by SV40LT and H-RasV12. However, their observations are based on much higher expression levels of H-RasV12 than in our study1 and Liang et al.’s study2. Our new RNA-seq data shows that NMR cells are strikingly more resistant to transcriptomic changes induced by oncogenic Ras than mouse, blind mole-rat, and human cells, revealing suppressed Ras signaling as an anti-cancer mechanism in NMR cells. Furthermore, we found that high expression of H-RasV12 abolished this mechanism and rendered NMR cells susceptible to oncogenic transformation. Our results explain that the ostensibly equal susceptibility of NMR and mouse cells to transformation observed by Hadi et al. was resulted from high levels of H-RasV12 overriding anti-cancer mechanisms of the naked mole rat.
SummaryEpigenetics has hitherto been studied and understood largely at the level of individual or... more SummaryEpigenetics has hitherto been studied and understood largely at the level of individual organisms. Here, we report a multi-faceted investigation of DNA methylation across 11,117 samples from 176 different species. We performed an unbiased clustering of individual cytosines into 55 modules and identified 31 modules related to primary traits including age, species lifespan, sex, adult species weight, tissue type and phylogenetic order. Analysis of the correlation between DNA methylation and species allowed us to construct phyloepigenetic trees for different tissues that parallel the phylogenetic tree. In addition, while some stable cytosines reflect phylogenetic signatures, others relate to age and lifespan, and in many cases responding to anti-aging interventions in mice such as caloric restriction and ablation of growth hormone receptors. Insights uncovered by this investigation have important implications for our understanding of the role of epigenetics in mammalian evolutio...
Southern blot analysis of HindIII-cleaved rickettsial DNA was used for genotypic characterization... more Southern blot analysis of HindIII-cleaved rickettsial DNA was used for genotypic characterization of the typhus group (TG) species (R. prowazekii, R. typhi, R. canada) and a few species of the spotted fever group (SFG) rickettsiae (R. sibirica, R. conorii, R. akari). Four different DNA probes were employed. PBH11 and PBH13 probes were morphospecific HindIII fragments of R. prowazekii DNA. MW218 probe contained the gene for 51 K antigen and MW264 probe contained the citrate synthase gene of R. prowazekii. All the probes hybridized with the tested TG and SFG rickettsial DNAs, forming from 1 to 5 bands, but they did not with R. tsutsugamushi or C. burnetii DNAs. All the probes demonstrated specific hybridization patterns with TG species and R. akari. PBH11, PBH13 and MW264 probes clearly distinguished R. sibirica and R. conorii from the other tested rickettsiae, but not from each other. However, these two species differed slightly with MW218 probe. Several strains of each species were ...
Molekuliarnaia genetika, mikrobiologiia i virusologiia, 1987
The DNA of Rickettsia provazekii strain E was cleaved by PstI restriction endonuclease under the ... more The DNA of Rickettsia provazekii strain E was cleaved by PstI restriction endonuclease under the conditions of partial restriction. The fragments were inserted into the PstI site of pBR325 and cloned in this plasmid. E. coli strain HB101 was used as a recipient for cloning. 880 clones sensitive to ampicillin and resistant to tetracycline were selected from 5120 transformants. The cloning of rickettsial DNA has been confirmed by the blot hybridization technique. Analysis of individual and net probes of the hybrid DNA by gel electrophoresis makes it possible to conclude that 90% of the selected clones harbour hybrid plasmids, the size of the cloned fragments rangers from 0.9 to 10.4 Kb, the obtained library of clones contains 70% of the whole genome of Rickettsia provazekii.
The DNA of Rickettsia prowazekii vaccine strain E was analysed by restriction analysis with 17 en... more The DNA of Rickettsia prowazekii vaccine strain E was analysed by restriction analysis with 17 endonucleases in comparison with its virulent revertant - Evir and the virulent reference strain Breinl. The DNA of cloned and uncloned strains showed identical restriction endonuclease patterns. In spite of stable differences in virulence, strains E and Evir displayed a totally identical DNA cleavage pattern indicating the absence of marked structural differences between their genomes. On the other hand 9 endonucleases showed differences in the restrictograms of the DNA strain Breinl as compared with strains E and Evir.
It has been independently demonstrated by us1 and Liang et al.2 that naked mole-rat (NMR) cells a... more It has been independently demonstrated by us1 and Liang et al.2 that naked mole-rat (NMR) cells are more resistant to SV40LT and H-RasV12-induced transformation than mouse cells. In the accompanying comment, Hadi et al. argued that NMR cells and mouse cells are equally susceptible to oncogenic transformation by SV40LT and H-RasV12. However, their observations are based on much higher expression levels of H-RasV12 than in our study1 and Liang et al.’s study2. Our new RNA-seq data shows that NMR cells are strikingly more resistant to transcriptomic changes induced by oncogenic Ras than mouse, blind mole-rat, and human cells, revealing suppressed Ras signaling as an anti-cancer mechanism in NMR cells. Furthermore, we found that high expression of H-RasV12 abolished this mechanism and rendered NMR cells susceptible to oncogenic transformation. Our results explain that the ostensibly equal susceptibility of NMR and mouse cells to transformation observed by Hadi et al. was resulted from high levels of H-RasV12 overriding anti-cancer mechanisms of the naked mole rat.
SummaryEpigenetics has hitherto been studied and understood largely at the level of individual or... more SummaryEpigenetics has hitherto been studied and understood largely at the level of individual organisms. Here, we report a multi-faceted investigation of DNA methylation across 11,117 samples from 176 different species. We performed an unbiased clustering of individual cytosines into 55 modules and identified 31 modules related to primary traits including age, species lifespan, sex, adult species weight, tissue type and phylogenetic order. Analysis of the correlation between DNA methylation and species allowed us to construct phyloepigenetic trees for different tissues that parallel the phylogenetic tree. In addition, while some stable cytosines reflect phylogenetic signatures, others relate to age and lifespan, and in many cases responding to anti-aging interventions in mice such as caloric restriction and ablation of growth hormone receptors. Insights uncovered by this investigation have important implications for our understanding of the role of epigenetics in mammalian evolutio...
Southern blot analysis of HindIII-cleaved rickettsial DNA was used for genotypic characterization... more Southern blot analysis of HindIII-cleaved rickettsial DNA was used for genotypic characterization of the typhus group (TG) species (R. prowazekii, R. typhi, R. canada) and a few species of the spotted fever group (SFG) rickettsiae (R. sibirica, R. conorii, R. akari). Four different DNA probes were employed. PBH11 and PBH13 probes were morphospecific HindIII fragments of R. prowazekii DNA. MW218 probe contained the gene for 51 K antigen and MW264 probe contained the citrate synthase gene of R. prowazekii. All the probes hybridized with the tested TG and SFG rickettsial DNAs, forming from 1 to 5 bands, but they did not with R. tsutsugamushi or C. burnetii DNAs. All the probes demonstrated specific hybridization patterns with TG species and R. akari. PBH11, PBH13 and MW264 probes clearly distinguished R. sibirica and R. conorii from the other tested rickettsiae, but not from each other. However, these two species differed slightly with MW218 probe. Several strains of each species were ...
Molekuliarnaia genetika, mikrobiologiia i virusologiia, 1987
The DNA of Rickettsia provazekii strain E was cleaved by PstI restriction endonuclease under the ... more The DNA of Rickettsia provazekii strain E was cleaved by PstI restriction endonuclease under the conditions of partial restriction. The fragments were inserted into the PstI site of pBR325 and cloned in this plasmid. E. coli strain HB101 was used as a recipient for cloning. 880 clones sensitive to ampicillin and resistant to tetracycline were selected from 5120 transformants. The cloning of rickettsial DNA has been confirmed by the blot hybridization technique. Analysis of individual and net probes of the hybrid DNA by gel electrophoresis makes it possible to conclude that 90% of the selected clones harbour hybrid plasmids, the size of the cloned fragments rangers from 0.9 to 10.4 Kb, the obtained library of clones contains 70% of the whole genome of Rickettsia provazekii.
The DNA of Rickettsia prowazekii vaccine strain E was analysed by restriction analysis with 17 en... more The DNA of Rickettsia prowazekii vaccine strain E was analysed by restriction analysis with 17 endonucleases in comparison with its virulent revertant - Evir and the virulent reference strain Breinl. The DNA of cloned and uncloned strains showed identical restriction endonuclease patterns. In spite of stable differences in virulence, strains E and Evir displayed a totally identical DNA cleavage pattern indicating the absence of marked structural differences between their genomes. On the other hand 9 endonucleases showed differences in the restrictograms of the DNA strain Breinl as compared with strains E and Evir.
Uploads