The Polycomb group （PcG） genes repress gene expression mainly through chromatin modifications and regulation of chromatin structure. At present, at/east four protein complexes of PcG proteins are identified, includi...The Polycomb group （PcG） genes repress gene expression mainly through chromatin modifications and regulation of chromatin structure. At present, at/east four protein complexes of PcG proteins are identified, including Polycomb repressive complex 1 （PRC1）, Polycomb repressive complex 2 （PRC2）, PHO-repressive complex （PhoRC） and Polycomb repressive deubiquitinase （PR-DUB）. In this review, the recent discoveries of the composition of the above complexes, as well as their roles in regulating histone modifications and gene silencing are discussed. We mainly focus on the composition of PRC1 and PRC2 complex and recruitment of PcG to target genes and mechanisms of PRC1 and PRC2-mediated gene silencing. Although much progress has been made in understanding gene silencing mediated by PcG proteins, we also discuss several important questions that still remained unanswered, such as the inheritance of histone modifications during cell division.展开更多
Soil fungi and aboveground plant play vital functions in terrestrial ecosystems,while the relationship between aboveground plant diversity and the unseen soil fungal diversity remains unclear.We established 6 sites fr...Soil fungi and aboveground plant play vital functions in terrestrial ecosystems,while the relationship between aboveground plant diversity and the unseen soil fungal diversity remains unclear.We established 6 sites from the west to the east of the temperate steppe that vary in plant diversity(plant species richness:7-32)to explore the relationship between soil fungal diversity and aboveground plant diversity.Soil fungal community was characterized by applying 18S rRNA gene sequencing using MiSeq PE300 and aligned with Silva 132 database.As a result,soil fungal community was predominately composed of species within the Ascomycota(84.36%),Basidiomycota(7.22%)and Mucoromycota(6.44%).Plant species richness occupied the largest explanatory power in structuring soil fungal community(19.05%–19.78%).The alpha(α)diversity of the whole soil fungi and Ascomycota showed a hump-backed pattern with increasing plant species richness,and the beta(β)diversity of the whole soil fungi and Ascomycota increased with increasing plantβdiversity.Those results indicated that soil fungi and external resources were well balanced at the 20-species level of plant and the sites were more distinct in the composition of their plant communities also harbored more distinct soil fungal communities.Thus,plant diversity could predict both soil fungalαandβdiversity in the temperate steppe of northeastern China.展开更多
基金Supported by the National Key Basic Research Program of China(973 Program)(2011CB504206,2012CB518700)the National Natural Science Foundation of China(91019013,31221061,31200653 and 31370866)Program for New Century Excellent Talents in University(NCET-11-0410)
文摘The Polycomb group （PcG） genes repress gene expression mainly through chromatin modifications and regulation of chromatin structure. At present, at/east four protein complexes of PcG proteins are identified, including Polycomb repressive complex 1 （PRC1）, Polycomb repressive complex 2 （PRC2）, PHO-repressive complex （PhoRC） and Polycomb repressive deubiquitinase （PR-DUB）. In this review, the recent discoveries of the composition of the above complexes, as well as their roles in regulating histone modifications and gene silencing are discussed. We mainly focus on the composition of PRC1 and PRC2 complex and recruitment of PcG to target genes and mechanisms of PRC1 and PRC2-mediated gene silencing. Although much progress has been made in understanding gene silencing mediated by PcG proteins, we also discuss several important questions that still remained unanswered, such as the inheritance of histone modifications during cell division.
基金This study was supported by the National Key Research and Development Program of China(2016YFC0502100)the Fundamental Research Funds for the Central Universities,Southwest Minzu University(2020NYBPY07).
文摘Soil fungi and aboveground plant play vital functions in terrestrial ecosystems,while the relationship between aboveground plant diversity and the unseen soil fungal diversity remains unclear.We established 6 sites from the west to the east of the temperate steppe that vary in plant diversity(plant species richness:7-32)to explore the relationship between soil fungal diversity and aboveground plant diversity.Soil fungal community was characterized by applying 18S rRNA gene sequencing using MiSeq PE300 and aligned with Silva 132 database.As a result,soil fungal community was predominately composed of species within the Ascomycota(84.36%),Basidiomycota(7.22%)and Mucoromycota(6.44%).Plant species richness occupied the largest explanatory power in structuring soil fungal community(19.05%–19.78%).The alpha(α)diversity of the whole soil fungi and Ascomycota showed a hump-backed pattern with increasing plant species richness,and the beta(β)diversity of the whole soil fungi and Ascomycota increased with increasing plantβdiversity.Those results indicated that soil fungi and external resources were well balanced at the 20-species level of plant and the sites were more distinct in the composition of their plant communities also harbored more distinct soil fungal communities.Thus,plant diversity could predict both soil fungalαandβdiversity in the temperate steppe of northeastern China.
