Heritable alteration in DNA methylation patterns was detected in all five rice lines with introgressed DNA segments from wild rice(Zizania latifolia(Griseb.))by DNA gel blotting analys iswith an endogenous retrotransp...Heritable alteration in DNA methylation patterns was detected in all five rice lines with introgressed DNA segments from wild rice(Zizania latifolia(Griseb.))by DNA gel blotting analys iswith an endogenous retrotransposon Tos/7as a probe.The changing patterns include simultaneous loss of parental fragments and appearance of novel fragments in each of the four methylation-sensitive enzyme digests.Methylation modifications include cytosines at both symmetrical and asymmetrical sites,as well as adenine bases.Sequence ana lysis at two critical regions of Tos/7,i.e.the 5'-LTR region(region I)and the reverse transcriptase region(region II)showed complete conservation for all five introgression lines compared with the parent.Sequence-specific PCR assay,however,confirmed that methylation changes occurred in both regions,Moreover,concordance in the collective methylation changes between 5'-LTR and RT regions was observed in two of the introgression lines.The methylation changes are stably inherited to the next generation.Because earlier studies showed that there had been activation and mobilization of Tos/7 in these introgression lines following alien DNA integration,it appears likely that DNA methylation may have played some roles in controlling activity of Tos/7in rice,although the exact relationship between the two phenomena remains to be established.展开更多
The karyotype of the primary wheat wheatgrass alien addition line TAI 27 was 2 n=44 in which all of the chromosomes were metacentric and submetacentric.However,in the progeny of TAI 27 a pair of chromosomes had become...The karyotype of the primary wheat wheatgrass alien addition line TAI 27 was 2 n=44 in which all of the chromosomes were metacentric and submetacentric.However,in the progeny of TAI 27 a pair of chromosomes had become small chromosomes in the two morphologically different plants.Fluorescence in situ hybridization(FISH)technique was used to analyze the two different plants.The observations indicate that a pair of small chromosomes in one variation line are from wheatgrass.In another variation line,a pair of small chromosomes are also from wheatgrass,while another pair of wheatgrass chromosomes have substituted the wheat chromosomes.TAI 27 and its variant lines showed a high level of resistance to barley yellow dwarf virus(BYDV).The possible explanation for such a variation and the potential use of the variant lines were discussed briefly.展开更多
The location and configuration of nucleolar DNA have not been determined for a long time. In this paper, we have observed the nucleolar infrastructure and the character of nucleolar DNA in Allium cepa cells by convent...The location and configuration of nucleolar DNA have not been determined for a long time. In this paper, we have observed the nucleolar infrastructure and the character of nucleolar DNA in Allium cepa cells by conventional electron microscopy and the cytochemical NAMA-Ur DNA specific staining method. Furthermore, we have properly improved the NAMA-Ur method so as to analyze the location and configuration of nucleolar DNA in situ. Our results indicated that the nucleolar DNA in Allium cepa cells is mainly located at the border between fibrillar centers and dense fibribllar component, especially distributed in the configuration of encircling the fibrillar centers.展开更多
By using the anti-RNA/DNA hybrid antibody as the probe, we labeled and analyzed the precise transcrip-tional sites of active genes in Allium cepa cells in situ. The results showed that the location of labeled signals ...By using the anti-RNA/DNA hybrid antibody as the probe, we labeled and analyzed the precise transcrip-tional sites of active genes in Allium cepa cells in situ. The results showed that the location of labeled signals appeared in mitochondrion was the same as that in chloroplast, generally concentrated at the central matrix space where there were no cristae and thylakoids. In the extranucleolar regions of nucleus, the labeled signals of transcriptional sites were situated at the perichromatin fibrils, which decondensed and stretched out from the chromosome territories. Our results also displayed the concentrations of labeled signals in a certain region of nucleus, and this means that the gene transcription rich region actually existed in Allium cepa cells. In nucleolus, the synthetic sites of rRNA were localized not only to the periphery of fibrillar centers but also to the DFC near FC.展开更多
基金Supported by the National Science Fund for Distinguished Young Scholars of China(30225003)the Outstanding Youth Research Plans of the Jilin Provincial Government
文摘Heritable alteration in DNA methylation patterns was detected in all five rice lines with introgressed DNA segments from wild rice(Zizania latifolia(Griseb.))by DNA gel blotting analys iswith an endogenous retrotransposon Tos/7as a probe.The changing patterns include simultaneous loss of parental fragments and appearance of novel fragments in each of the four methylation-sensitive enzyme digests.Methylation modifications include cytosines at both symmetrical and asymmetrical sites,as well as adenine bases.Sequence ana lysis at two critical regions of Tos/7,i.e.the 5'-LTR region(region I)and the reverse transcriptase region(region II)showed complete conservation for all five introgression lines compared with the parent.Sequence-specific PCR assay,however,confirmed that methylation changes occurred in both regions,Moreover,concordance in the collective methylation changes between 5'-LTR and RT regions was observed in two of the introgression lines.The methylation changes are stably inherited to the next generation.Because earlier studies showed that there had been activation and mobilization of Tos/7 in these introgression lines following alien DNA integration,it appears likely that DNA methylation may have played some roles in controlling activity of Tos/7in rice,although the exact relationship between the two phenomena remains to be established.
文摘The karyotype of the primary wheat wheatgrass alien addition line TAI 27 was 2 n=44 in which all of the chromosomes were metacentric and submetacentric.However,in the progeny of TAI 27 a pair of chromosomes had become small chromosomes in the two morphologically different plants.Fluorescence in situ hybridization(FISH)technique was used to analyze the two different plants.The observations indicate that a pair of small chromosomes in one variation line are from wheatgrass.In another variation line,a pair of small chromosomes are also from wheatgrass,while another pair of wheatgrass chromosomes have substituted the wheat chromosomes.TAI 27 and its variant lines showed a high level of resistance to barley yellow dwarf virus(BYDV).The possible explanation for such a variation and the potential use of the variant lines were discussed briefly.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 39770367).
文摘The location and configuration of nucleolar DNA have not been determined for a long time. In this paper, we have observed the nucleolar infrastructure and the character of nucleolar DNA in Allium cepa cells by conventional electron microscopy and the cytochemical NAMA-Ur DNA specific staining method. Furthermore, we have properly improved the NAMA-Ur method so as to analyze the location and configuration of nucleolar DNA in situ. Our results indicated that the nucleolar DNA in Allium cepa cells is mainly located at the border between fibrillar centers and dense fibribllar component, especially distributed in the configuration of encircling the fibrillar centers.
基金the National Natural Science Foundation of China (Grant No. 39770367) and the Special Funds for the National Major Basic Research Program of China (Grant No. G19990539).
文摘By using the anti-RNA/DNA hybrid antibody as the probe, we labeled and analyzed the precise transcrip-tional sites of active genes in Allium cepa cells in situ. The results showed that the location of labeled signals appeared in mitochondrion was the same as that in chloroplast, generally concentrated at the central matrix space where there were no cristae and thylakoids. In the extranucleolar regions of nucleus, the labeled signals of transcriptional sites were situated at the perichromatin fibrils, which decondensed and stretched out from the chromosome territories. Our results also displayed the concentrations of labeled signals in a certain region of nucleus, and this means that the gene transcription rich region actually existed in Allium cepa cells. In nucleolus, the synthetic sites of rRNA were localized not only to the periphery of fibrillar centers but also to the DFC near FC.
