The Experts below are selected from a list of 3198 Experts worldwide ranked by ideXlab platform
Sei-ichi Kohno - One of the best experts on this subject based on the ideXlab platform.
-
Whole Chromosome Elimination and Chromosome terminus Elimination both contribute to somatic differentiation in Taiwanese hagfish Paramyxine sheni
Chromosome Research, 2010Co-Authors: Noriko F. Kojima, Kenji K. Kojima, Shuichi Kobayakawa, Naoki Higashide, Chiemi Hamanaka, Ayumi Nitta, Ikuyo Koeda, Toru Yamaguchi, Motoharu Shichiri, Sei-ichi KohnoAbstract:Chromosome Elimination is a process in which some chromatins are discarded from the presumptive somatic cells during early embryogenesis. Eliminated chromatins in hagfish generally consist of repetitive sequences, and they are highly heterochromatinized in germ cells. In this study, we characterized four novel eliminated DNA families, EEPs1–4, from the Taiwanese hagfish Paramyxine sheni . Sequences of these four elements occupied 20–27% of eliminated DNA in total, and each family was arranged mainly in tandem in the germline genome with high copy numbers. Although most of these elements were eliminated, a minor fraction remained in somatic cells. Some eliminated DNA families are shared as eliminated sequences between Eptatretidae and Myxinidae. Fluorescence in situ hybridization (FISH) of these elements showed that not only heterochromatic Chromosomes but also both ends of euchromatic Chromosomes in germ cells are absent in somatic cells of P. sheni . It strongly suggests that Chromosome terminus Elimination, in addition to whole Chromosome Elimination, contributes to somatic Chromosome differentiation. Telomere-FISH further showed that Chromosome fragmentation and the subsequent de novo addition of telomeric repeats are the likely mechanisms underlying Chromosome terminus Elimination. These characteristics make it indispensable to study the evolution and mechanisms underlying Chromosome Elimination in hagfish.
-
Whole Chromosome Elimination and Chromosome terminus Elimination both contribute to somatic differentiation in Taiwanese hagfish Paramyxine sheni
Chromosome Research, 2010Co-Authors: Noriko F. Kojima, Kenji K. Kojima, Shuichi Kobayakawa, Naoki Higashide, Chiemi Hamanaka, Ayumi Nitta, Ikuyo Koeda, Toru Yamaguchi, Motoharu Shichiri, Sei-ichi KohnoAbstract:Chromosome Elimination is a process in which some chromatins are discarded from the presumptive somatic cells during early embryogenesis. Eliminated chromatins in hagfish generally consist of repetitive sequences, and they are highly heterochromatinized in germ cells. In this study, we characterized four novel eliminated DNA families, EEPs1-4, from the Taiwanese hagfish Paramyxine sheni. Sequences of these four elements occupied 20-27% of eliminated DNA in total, and each family was arranged mainly in tandem in the germline genome with high copy numbers. Although most of these elements were eliminated, a minor fraction remained in somatic cells. Some eliminated DNA families are shared as eliminated sequences between Eptatretidae and Myxinidae. Fluorescence in situ hybridization (FISH) of these elements showed that not only heterochromatic Chromosomes but also both ends of euchromatic Chromosomes in germ cells are absent in somatic cells of P. sheni. It strongly suggests that Chromosome terminus Elimination, in addition to whole Chromosome Elimination, contributes to somatic Chromosome differentiation. Telomere-FISH further showed that Chromosome fragmentation and the subsequent de novo addition of telomeric repeats are the likely mechanisms underlying Chromosome terminus Elimination. These characteristics make it indispensable to study the evolution and mechanisms underlying Chromosome Elimination in hagfish.
-
Chromatin Diminution and Chromosome Elimination in Hagfishes
The Biology of Hagfishes, 1998Co-Authors: Sei-ichi Kohno, Souichirou Kubota, Yasuharu NakaiAbstract:Morphological analyses of mitotic and meiotic Chromosomes were performed in hagfish species. The kinetochores in both types of Chromosomes appeared as a three-layered structure along the surfaces of Chromosomes (12–50% of the length of the Chromosome) without any constriction. There are no similar reports at present in other vertebrates with long kinetochores.
-
Chromosome Elimination in three Baltic, south Pacific and north-east Pacific hagfish species.
Chromosome Research, 1995Co-Authors: Yasuharu Nakai, Souichirou Kubota, Yuji Goto, Takeshi Ishibashi, William Davison, Sei-ichi KohnoAbstract:We have confirmed that Chromosome Elimination occurs in the cells ofMyxine glutinosa, collected from the Baltic Sea off Sweden,Eptatretus cirrhatus from the south Pacific Ocean off the east coast of New Zealand, andE. stoutii from the north-east Pacific Ocean off Canada, similar to cells of four Japanese hagfish species. InM. Glutinosa, E. cirrhatus type A,E. cirrhatus type B andE. stoutii, the differences in Chromosome number between spermatogonia (44, 72, 80 and 48) and somatic cells (28, 34, 34 and 34) were 16, 38, 46 and 14 respectively. The amount of DNA eliminated from presumptive somatic cells averaged 43.5%, 48.7%, 54.6% and 52.8% respectively. Euchromatic Chromosomes and/or parts of Chromosomes in addition to heterochromatic Chromosomes were clearly eliminated inE. cirrhatus andE. stoutii. Adding our previous observations of four Japanese hagfish species, Chromosome Elimination occurs in all seven of the hagfish species. These results suggest that this phenomenon, Chromosome Elimination, generally occurs in the order Myxinida. In addition, B-Chromosomes were observed in the germ cells ofE. cirrhatus andE. stoutii, similar to the cells ofE. okinoseanus, E. burgeri andParamyxine atami (E. atami). This fact suggests that B-Chromosomes might exist generally in the family Eptatretidae.
-
Chromatin diminution and Chromosome Elimination in four Japanese hagfish species.
Cytogenetic and Genome Research, 1991Co-Authors: Y. Nakai, Souichirou Kubota, Sei-ichi KohnoAbstract:Cytogenetic examination of four Japanese hagfish species belonging to the order Myxinida (Eptatretus okinoseanus, E. burgeri, Paramyxine atami, and Myxine garmani) revealed differences in Chromosome number between germ cells (spermatocytes and spermatogonia) and somatic cells (liver, blood, gill, and kidney). The differences in Chromosome number between spermatogonia (54, 52, 48, and 16) and somatic cells (34, 36, 34, and 14) were 20, 16, 14, and 2 in E. okinoseanus, E. burgeri, P. atami, and M. garmani, respectively. The amount of DNA in a somatic cell (2C) relative to that in a germ cell (2C) averaged 54.6% (E. okinoseanus type A), 44.9% (E. okinoseanus type B), 79.1 % (E. burgeri), 60.0% (P. atami), and 70.2 % (M. garmani). These results clearly indicate that Chromosome Elimination takes place during early cleavage in the four hagfish species of Myxinida living in Japanese waters, except in the ancestral germline cells. C-banding of metaphase Chromosome preparations of germline and somatic cells from each hagfish species revealed that the C-band-positive chromatin in the ancestral somatic cells had been almost completely eliminated. Three patterns of Elimination of this chromatin are discussed.
H. K. Chaudhary - One of the best experts on this subject based on the ideXlab platform.
-
In vivo colchicine manipulation for enhancing DH production efficiency in Triticum durum using Imperata cylindrica-mediated Chromosome Elimination approach
Cereal Research Communications, 2020Co-Authors: I. Mehta, H. K. Chaudhary, P. Sharma, N. V. Manoj, K. Singh, R. S. SranAbstract:Durum wheat × Imperata cylindrica hybridization was carried out utilizing two durum wheat genotypes as maternal parents (A-9-30-1 and PDW 314) and I. cylindrica as a pollen source followed by in vivo application of colchicine to establish a standard protocol for colchicine application aimed at enhancement of doubled haploid production in durum wheat. Various concentrations of colchicine ranging from 500 to 7000 ppm were injected to the pollinated spikes at different time interval viz., 24 h, 48 h and 72 h after pollination. Application of 5000–7000 ppm colchicine at 48 h after pollination was established as the optimum colchicine dose for Chromosome doubling as confirmed through cytological studies in durum wheat using I. cylindrica-mediated Chromosome Elimination approach. PDW 314 was identified as a durum wheat genotype having more potential for doubled haploid induction via in vivo colchicine application than A-9-30-1. Identification of optimum dose of colchicine for application at in vivo level for induction of doubled haploids has opened new vistas in durum wheat improvement programme.
-
Recent Advances in Chromosome Elimination-Mediated Doubled Haploidy Breeding: Focus on Speed Breeding in Bread and Durum Wheats
Accelerated Plant Breeding Volume 1, 2020Co-Authors: H. K. Chaudhary, Anila Badiyal, N. S. Jamwal, P. Sharma, N. V. Manoj, K. SinghAbstract:In the scenario of catastrophic climatic change, burgeoning population, reduction in cultivable land due to urbanization and continuously changing abiotic as well as biotic stresses, wheat production is facing a continuous threat for reduction. Scientific community worldwide has joined hands to tackle this problem with the integration of novel technologies in cropping system. Among such technologies, doubled haploid (DH) production has revolutionized wheat cultivation with far-reaching implications in accelerating the crop improvement programmes with enhanced precision. It has been a boon for the wheat breeders to discover Chromosome Elimination—a dynamic process occurring during wide hybridization in wheat with various genera of Poaceae. Earlier thought to be an obstacle in successful wide hybridization, it has now become a perfect tool for haploid induction in wheat. Since the invention of bulbosum approach, scientists have exploited other potential systems like wheat × maize and wheat × Imperata cylindrica leading to selective Chromosome Elimination. Recently, I. cylindrica-mediated approach has emerged as an efficient alternative to the widely used maize-mediated system as it enjoys the benefits of natural coincidence for flowering with that of wheat, abundant pollen supply for longer span, pollen with greater longevity and inducing significantly higher frequency of doubled haploids from wheat as well as triticale × wheat and wheat × rye derivatives. The I. cylindrica-mediated system has evinced appreciable performance for the triticale × wheat derivatives where maize-mediated system remained unsuccessful. Chromosome Elimination-mediated DH breeding has emerged as a milestone for the acceleration of various wheat genetic upgradation programmes.
-
New frontiers in doubled haploidy breeding in wheat
Agricultural Research Journal, 2015Co-Authors: H. K. Chaudhary, Anila Badiyal, Navdeep S JamwalAbstract:Modern agricultural research is focused on the combination of genomes from diverse genetic backgrounds through wide hybridization for sustainable improvement of crop species. Recovery of stable hybrids in certain intergeneric crosses becomes sometimes cumbersome due to preferential uniparental Chromosome Elimination, a bane for the breeders. This Chromosome Elimination phenomenon has been turned out into boon through doubled haploidy breeding enabling instant and proficient recovery of haploids and the homozygous recombinants from such crosses in a staple crop like wheat. Many approaches for haploid induction in wheat have been practiced across the world including gametogenic embryogenesis and wide hybridization with distant relatives or wild progenitors. Amongst wide hybridization approaches utilizing Chromosome Elimination technique in wheat, bulbosum approach took lead but failed due to its genotypic specificity and hence having limited application. Though wheat x maize system, exhibiting genotypic non-specificity, has been utilized for haploidy breeding on large scale but it has failed to produce desirable results in wheat x rye as well as triticale x wheat derivatives. Lately, Imperata cylindrica-mediated Chromosome Elimination approach has emerged as an highly efficient alternative to the previous approaches for haploid induction in wheat. The invention of this approach has recorded a striking success not only in wheat, but has also succeeded in inducing appreciable number of haploids in wheat x rye and triticale x wheat derivatives as well as in the durum wheat. The novel tools like GISH and FISH of the molecular cytogenetic approach were used to identify, detect and track the Elimination of the I. cylindrica Chromosomes in wheat x I. cylindrica hybrids at different stages of the mitotic division which enunciated quick Elimination of the Chromosomes in the first division and attributed to higher recovery of the haploid embryos. The first doubled haploid wheat variety of the country named Him Pratham has been developed and released by utilizing the Chromosome Elimination approach of doubled haploidy breeding. Many innovative protocols of Chromosome Elimination approach were further developed for enhancing the haploid induction efficiency manifolds. The present article reviews various haploid induction approaches being undertaken across the globe and assesses them on account of their haploid induction efficiency in wheat.
-
Proportional Contribution and Potential of Maternal and Paternal Genotypes for Polyhaploid Induction in Wheat × Imperata cylindrica Chromosome Elimination Approach
Cereal Research Communications, 2014Co-Authors: S. A. Rather, H. K. Chaudhary, V. KailaAbstract:The Imperata cylindrica -mediated Chromosome Elimination approach has been identified as the most efficient system of doubled haploidy breeding in wheat ( Triticum aestivum L.). The present investigation was carried out to assess the mean performance of diverse I. cylindrica genotypes (five) collected from different locations and wheat F_1s (21) generated out of various elite winter and spring wheat ecotypes. Also, the proportional contribution of wheat F_1s and I. cylindrica genotypes was evaluated to find out the relative contribution of maternal and paternal parents to haploid induction. The investigation revealed that the mean response of wheat and I. cylindrica to haploid induction parameters, viz. pseudoseed formation, embryo formation, haploid regeneration and haploid formation varies from wheat and I. cylindrica genotype to genotype. The I. cylindrica genotype, Ic-Aru from north east Himalayas and wheat genotype, DH 114 × KWS 29 exhibited highest mean performance to haploid embryo formation, the stage for which all the three contributors, that is, wheat F_1s, I. cylindrica genotypes and wheat × I. cylindrica interaction were found to be similar for their proportional contribution (%) towards haploid induction. Thus, concluding that the haploid induction through preferential Chromosome Elimination approaches can be enhanced by using more efficient pollinators.
-
proportional contribution and potential of maternal and paternal genotypes for polyhaploid induction in wheat imperata cylindrica Chromosome Elimination approach
Cereal Research Communications, 2014Co-Authors: S. A. Rather, H. K. Chaudhary, V. KailaAbstract:The Imperata cylindrica-mediated Chromosome Elimination approach has been identified as the most efficient system of doubled haploidy breeding in wheat (Triticum aestivum L.). The present investigation was carried out to assess the mean performance of diverse I. cylindrica genotypes (five) collected from different locations and wheat F1s (21) generated out of various elite winter and spring wheat ecotypes. Also, the proportional contribution of wheat F1s and I. cylindrica genotypes was evaluated to find out the relative contribution of maternal and paternal parents to haploid induction. The investigation revealed that the mean response of wheat and I. cylindrica to haploid induction parameters, viz. pseudoseed formation, embryo formation, haploid regeneration and haploid formation varies from wheat and I. cylindrica genotype to genotype. The I. cylindrica genotype, Ic-Aru from north east Himalayas and wheat genotype, DH 114 × KWS 29 exhibited highest mean performance to haploid embryo formation, the stage...
Yu Wei - One of the best experts on this subject based on the ideXlab platform.
-
crispr cas9 mediated targeted Chromosome Elimination
Genome Biology, 2017Co-Authors: Erwei Zuo, Yidi Sun, Xuan Yao, Xiaona Huo, Jianhang Yin, Linyu Shi, Jie Ping, Xing Wang, Yu WeiAbstract:The CRISPR/Cas9 system has become an efficient gene editing method for generating cells carrying precise gene mutations, including the rearrangement and deletion of chromosomal segments. However, whether an entire Chromosome could be eliminated by this technology is still unknown. Here we demonstrate the use of the CRISPR/Cas9 system to eliminate targeted Chromosomes. Using either multiple cleavages induced by a single-guide RNA (sgRNA) that targets multiple Chromosome-specific sites or a cocktail of multiple sgRNAs, each targeting one specific site, we found that a sex Chromosome could be selectively eliminated in cultured cells, embryos, and tissues in vivo. Furthermore, this approach was able to produce a targeted autosome loss in aneuploid mouse embryonic stem cells with an extra human Chromosome and human induced pluripotent stem cells with trisomy 21, as well as cancer cells. CRISPR/Cas9-mediated targeted Chromosome Elimination offers a new approach to develop animal models with Chromosome deletions, and a potential therapeutic strategy for human aneuploidy diseases involving additional Chromosomes.
Noriko F. Kojima - One of the best experts on this subject based on the ideXlab platform.
-
Whole Chromosome Elimination and Chromosome terminus Elimination both contribute to somatic differentiation in Taiwanese hagfish Paramyxine sheni
Chromosome Research, 2010Co-Authors: Noriko F. Kojima, Kenji K. Kojima, Shuichi Kobayakawa, Naoki Higashide, Chiemi Hamanaka, Ayumi Nitta, Ikuyo Koeda, Toru Yamaguchi, Motoharu Shichiri, Sei-ichi KohnoAbstract:Chromosome Elimination is a process in which some chromatins are discarded from the presumptive somatic cells during early embryogenesis. Eliminated chromatins in hagfish generally consist of repetitive sequences, and they are highly heterochromatinized in germ cells. In this study, we characterized four novel eliminated DNA families, EEPs1–4, from the Taiwanese hagfish Paramyxine sheni . Sequences of these four elements occupied 20–27% of eliminated DNA in total, and each family was arranged mainly in tandem in the germline genome with high copy numbers. Although most of these elements were eliminated, a minor fraction remained in somatic cells. Some eliminated DNA families are shared as eliminated sequences between Eptatretidae and Myxinidae. Fluorescence in situ hybridization (FISH) of these elements showed that not only heterochromatic Chromosomes but also both ends of euchromatic Chromosomes in germ cells are absent in somatic cells of P. sheni . It strongly suggests that Chromosome terminus Elimination, in addition to whole Chromosome Elimination, contributes to somatic Chromosome differentiation. Telomere-FISH further showed that Chromosome fragmentation and the subsequent de novo addition of telomeric repeats are the likely mechanisms underlying Chromosome terminus Elimination. These characteristics make it indispensable to study the evolution and mechanisms underlying Chromosome Elimination in hagfish.
-
Whole Chromosome Elimination and Chromosome terminus Elimination both contribute to somatic differentiation in Taiwanese hagfish Paramyxine sheni
Chromosome Research, 2010Co-Authors: Noriko F. Kojima, Kenji K. Kojima, Shuichi Kobayakawa, Naoki Higashide, Chiemi Hamanaka, Ayumi Nitta, Ikuyo Koeda, Toru Yamaguchi, Motoharu Shichiri, Sei-ichi KohnoAbstract:Chromosome Elimination is a process in which some chromatins are discarded from the presumptive somatic cells during early embryogenesis. Eliminated chromatins in hagfish generally consist of repetitive sequences, and they are highly heterochromatinized in germ cells. In this study, we characterized four novel eliminated DNA families, EEPs1-4, from the Taiwanese hagfish Paramyxine sheni. Sequences of these four elements occupied 20-27% of eliminated DNA in total, and each family was arranged mainly in tandem in the germline genome with high copy numbers. Although most of these elements were eliminated, a minor fraction remained in somatic cells. Some eliminated DNA families are shared as eliminated sequences between Eptatretidae and Myxinidae. Fluorescence in situ hybridization (FISH) of these elements showed that not only heterochromatic Chromosomes but also both ends of euchromatic Chromosomes in germ cells are absent in somatic cells of P. sheni. It strongly suggests that Chromosome terminus Elimination, in addition to whole Chromosome Elimination, contributes to somatic Chromosome differentiation. Telomere-FISH further showed that Chromosome fragmentation and the subsequent de novo addition of telomeric repeats are the likely mechanisms underlying Chromosome terminus Elimination. These characteristics make it indispensable to study the evolution and mechanisms underlying Chromosome Elimination in hagfish.
Jie Ping - One of the best experts on this subject based on the ideXlab platform.
-
CRISPR/Cas9-mediated targeted Chromosome Elimination
Genome Biology, 2017Co-Authors: Erwei Zuo, Yidi Sun, Xuan Yao, Xiaona Huo, Jianhang Yin, Bingbing He, Linyu Shi, Xinde Hu, Xing Wang, Jie PingAbstract:BackgroundThe CRISPR/Cas9 system has become an efficient gene editing method for generating cells carrying precise gene mutations, including the rearrangement and deletion of chromosomal segments. However, whether an entire Chromosome could be eliminated by this technology is still unknown.ResultsHere we demonstrate the use of the CRISPR/Cas9 system to eliminate targeted Chromosomes. Using either multiple cleavages induced by a single-guide RNA (sgRNA) that targets multiple Chromosome-specific sites or a cocktail of multiple sgRNAs, each targeting one specific site, we found that a sex Chromosome could be selectively eliminated in cultured cells, embryos, and tissues in vivo. Furthermore, this approach was able to produce a targeted autosome loss in aneuploid mouse embryonic stem cells with an extra human Chromosome and human induced pluripotent stem cells with trisomy 21, as well as cancer cells.ConclusionsCRISPR/Cas9-mediated targeted Chromosome Elimination offers a new approach to develop animal models with Chromosome deletions, and a potential therapeutic strategy for human aneuploidy diseases involving additional Chromosomes.
-
CRISPR/Cas9-mediated targeted Chromosome Elimination
Genome Biology, 2017Co-Authors: Erwei Zuo, Yidi Sun, Xuan Yao, Xiaona Huo, Jianhang Yin, Linyu Shi, Xing Wang, Jie PingAbstract:The CRISPR/Cas9 system has become an efficient gene editing method for generating cells carrying precise gene mutations, including the rearrangement and deletion of chromosomal segments. However, whether an entire Chromosome could be eliminated by this technology is still unknown. Here we demonstrate the use of the CRISPR/Cas9 system to eliminate targeted Chromosomes. Using either multiple cleavages induced by a single-guide RNA (sgRNA) that targets multiple Chromosome-specific sites or a cocktail of multiple sgRNAs, each targeting one specific site, we found that a sex Chromosome could be selectively eliminated in cultured cells, embryos, and tissues in vivo. Furthermore, this approach was able to produce a targeted autosome loss in aneuploid mouse embryonic stem cells with an extra human Chromosome and human induced pluripotent stem cells with trisomy 21, as well as cancer cells. CRISPR/Cas9-mediated targeted Chromosome Elimination offers a new approach to develop animal models with Chromosome deletions, and a potential therapeutic strategy for human aneuploidy diseases involving additional Chromosomes.
-
crispr cas9 mediated targeted Chromosome Elimination
Genome Biology, 2017Co-Authors: Erwei Zuo, Yidi Sun, Xuan Yao, Xiaona Huo, Jianhang Yin, Linyu Shi, Jie Ping, Xing Wang, Yu WeiAbstract:The CRISPR/Cas9 system has become an efficient gene editing method for generating cells carrying precise gene mutations, including the rearrangement and deletion of chromosomal segments. However, whether an entire Chromosome could be eliminated by this technology is still unknown. Here we demonstrate the use of the CRISPR/Cas9 system to eliminate targeted Chromosomes. Using either multiple cleavages induced by a single-guide RNA (sgRNA) that targets multiple Chromosome-specific sites or a cocktail of multiple sgRNAs, each targeting one specific site, we found that a sex Chromosome could be selectively eliminated in cultured cells, embryos, and tissues in vivo. Furthermore, this approach was able to produce a targeted autosome loss in aneuploid mouse embryonic stem cells with an extra human Chromosome and human induced pluripotent stem cells with trisomy 21, as well as cancer cells. CRISPR/Cas9-mediated targeted Chromosome Elimination offers a new approach to develop animal models with Chromosome deletions, and a potential therapeutic strategy for human aneuploidy diseases involving additional Chromosomes.