Most of the plant homeodomain-containing proteins play important roles in regulating cell differentiation and organ development,and Arabidopsis GLABRA2(GL2),a member of the class IV homeodomain-Leucine zipper(HD-ZIP) ...Most of the plant homeodomain-containing proteins play important roles in regulating cell differentiation and organ development,and Arabidopsis GLABRA2(GL2),a member of the class IV homeodomain-Leucine zipper(HD-ZIP) proteins,is a trichome and non-root hair cell regulator.We展开更多
Homeobox genes have been discovered in many species. These genes are known to play a major role in specifying regional identity along the anterior-posterior axis of animals from a wide range of phyla.The products of t...Homeobox genes have been discovered in many species. These genes are known to play a major role in specifying regional identity along the anterior-posterior axis of animals from a wide range of phyla.The products of the homeotic genes are a set of evolutionarily conserved transcription factors that control elaborate developmental processes and specify cell fates in metazoans. Crustacean, presenting a variety of body plans not encountered in any other class or phylum of the Metazoa, has been shown to possess a single set of homologous Hox genes like insect. The ancestral crustacean Hox gene complex comprised ten genes: eight homologous to the hometic Hox genes and two related to nonhomeotic genes presented within the insect Hox complexes. The crustacean in particular exhibits an abundant diversity segment specialization and tagmosis. This morphological diversity relates to the Hox genes. In crustacean body plan, different Hox genes control different segments and tagmosis.展开更多
Deep skin wounds heal by scar formation with a Joss of its original appearance, structure and function.However, when the same damage occurs to the skin of an early gestational fetus, complete regeneration can be obser...Deep skin wounds heal by scar formation with a Joss of its original appearance, structure and function.However, when the same damage occurs to the skin of an early gestational fetus, complete regeneration can be observed. Despite significant research in the field of skin regeneration, many mysteries remain, such as the loss of wound healing ability with maturity, the differences in healing at different parts of the body, and the presence of hypertrophic scars and keloids in some races but not in others. The finding of HOX genes in the skin provides new explanations to these conundrums.展开更多
The diversity of body plans of mammals accelerates the innovation of lifestyles and the extensive adaptation to different habitats,including terrestrial,aerial and aquatic habitats.However,the genetic basis of those p...The diversity of body plans of mammals accelerates the innovation of lifestyles and the extensive adaptation to different habitats,including terrestrial,aerial and aquatic habitats.However,the genetic basis of those phenotypic modifications,which have occurred during mammalian evolution,remains poorly explored.In the present study,we synthetically surveyed the evolutionary pattern of Hox clusters that played a powerful role in the morphogenesis along the head-tail axis of animal embryos and the main regulatory factors(Mll,Bmi1 and E2f6)that control the expression of Hox genes.A deflected density of repetitive elements and lineage-specific radical mutations of Mll have been determined in marine mammals with morphological changes,suggesting that evolutionary changes may alter Hox gene expression in these lineages,leading to the morphological modification of these lineages.Although no positive selection was detected at certain ancestor nodes of lineages,the increasedωvalues of Hox genes implied the relaxation of functional constraints of these genes during the mammalian evolutionary process.More importantly,49 positively-selected sites were identified in mammalian lineages with phenotypic modifications,indicating adaptive evolution acting on Hox genes and regulatory factors.In addition,3 parallel amino acid substitutions in some Hox genes were examined in marine mammals,which might be responsible for their streamlined body.展开更多
The discovery of the homeobox motif and its presence in each gene of the Hox clusters revolutionized the fields of developmental biology and evolutionary developmental biology （1, 2）, providing a rapid entrance into...The discovery of the homeobox motif and its presence in each gene of the Hox clusters revolutionized the fields of developmental biology and evolutionary developmental biology （1, 2）, providing a rapid entrance into investigating the mechanisms of development of almost any animal taxon as well as dramatically altering conceptions on the extent of genetic conservation across the animal kingdom.展开更多
Archetypes of histone modifications associated with diverse chromosomal states that regulate access to DNA are leading the hypothesis of the histone code(or epigenetic code). However, it is still not evident how these...Archetypes of histone modifications associated with diverse chromosomal states that regulate access to DNA are leading the hypothesis of the histone code(or epigenetic code). However, it is still not evident how these post-translational modifications of histone tails lead to changes in chromatin structure. Histone modifications are able to activate and/or inactivate several genes and can be transmitted to next generation cells due to an epigenetic memory. The challenging issue is to identify or "decrypt" the code used to transmit these modifications to descent cells. Here, an attempt is made to describe how histone modifications operate as part of histone code that stipulates patterns of gene expression. This papers emphasizes particularly on the correlation between histone modifications and patterns of Hox gene expression in Caenorhabditis elegans. This work serves as an example to illustrate the power of the epigenetic machinery and its use in drug design and discovery.展开更多
The three-dimensional(3D) organization of the eukaryotic genome is critical for its proper function. Evidence suggests that extensive chromatin loops form the building blocks of the genomic architecture, separating ge...The three-dimensional(3D) organization of the eukaryotic genome is critical for its proper function. Evidence suggests that extensive chromatin loops form the building blocks of the genomic architecture, separating genes and gene clusters into distinct functional domains. These loops are anchored in part by a special type of DNA elements called chromatin boundary elements(CBEs). CBEs were originally found to insulate neighboring genes by blocking influences of transcriptional enhancers or the spread of silent chromatin. However, recent results show that chromatin loops can also play a positive role in gene regulation by looping out intervening DNA and "delivering" remote enhancers to gene promoters. In addition, studies from human and model organisms indicate that the configuration of chromatin loops, many of which are tethered by CBEs, is dynamically regulated during cell differentiation. In particular, a recent work by Li et al has shown that the SF1 boundary, located in the Drosophila Hox cluster, regulates local genes by tethering different subsets of chromatin loops: One subset enclose a neighboring gene ftz, limiting its access by the surrounding Scr enhancers and restrict the spread of repressive histones during early embryogenesis; and the other loops subdivide the Scr regulatory region into independent domains of enhancer accessibility. The enhancer-blocking activity of these CBE elements varies greatly in strength and tissue distribution. Further, tandem pairing of SF1 and SF2 facilitate the bypass of distal enhancers in transgenic flies, providing a mechanism for endogenous enhancers to circumvent genomic interruptions resulting from chromosomal rearrangement. This study demonstrates how a network of chromatin boundaries, centrally organized by SF1, can remodel the 3D genome to facilitate gene regulation during development.展开更多
文摘Most of the plant homeodomain-containing proteins play important roles in regulating cell differentiation and organ development,and Arabidopsis GLABRA2(GL2),a member of the class IV homeodomain-Leucine zipper(HD-ZIP) proteins,is a trichome and non-root hair cell regulator.We
文摘Homeobox genes have been discovered in many species. These genes are known to play a major role in specifying regional identity along the anterior-posterior axis of animals from a wide range of phyla.The products of the homeotic genes are a set of evolutionarily conserved transcription factors that control elaborate developmental processes and specify cell fates in metazoans. Crustacean, presenting a variety of body plans not encountered in any other class or phylum of the Metazoa, has been shown to possess a single set of homologous Hox genes like insect. The ancestral crustacean Hox gene complex comprised ten genes: eight homologous to the hometic Hox genes and two related to nonhomeotic genes presented within the insect Hox complexes. The crustacean in particular exhibits an abundant diversity segment specialization and tagmosis. This morphological diversity relates to the Hox genes. In crustacean body plan, different Hox genes control different segments and tagmosis.
基金This study was supported by a grant from Key Project of National Natural Science Foundation （No. 30730092）.
文摘Deep skin wounds heal by scar formation with a Joss of its original appearance, structure and function.However, when the same damage occurs to the skin of an early gestational fetus, complete regeneration can be observed. Despite significant research in the field of skin regeneration, many mysteries remain, such as the loss of wound healing ability with maturity, the differences in healing at different parts of the body, and the presence of hypertrophic scars and keloids in some races but not in others. The finding of HOX genes in the skin provides new explanations to these conundrums.
基金This work was supported by the National Natural Science Funds for Distinguished Young Scholars to G.Y.(grant number 31325025)the State Key Program of National Natural Science Foundation of China(NSFC)(grant number 31630071)+2 种基金the NSFC(grant numbers 31570379 to S.X.,31370401 to W.R.)the Priority Academic Program Development of Jiangsu Higher Education Institutions to G.Y.and S.X.the Natural Science Foundation of Jiangsu Province of China(grant number BK20141449)to S.X.
文摘The diversity of body plans of mammals accelerates the innovation of lifestyles and the extensive adaptation to different habitats,including terrestrial,aerial and aquatic habitats.However,the genetic basis of those phenotypic modifications,which have occurred during mammalian evolution,remains poorly explored.In the present study,we synthetically surveyed the evolutionary pattern of Hox clusters that played a powerful role in the morphogenesis along the head-tail axis of animal embryos and the main regulatory factors(Mll,Bmi1 and E2f6)that control the expression of Hox genes.A deflected density of repetitive elements and lineage-specific radical mutations of Mll have been determined in marine mammals with morphological changes,suggesting that evolutionary changes may alter Hox gene expression in these lineages,leading to the morphological modification of these lineages.Although no positive selection was detected at certain ancestor nodes of lineages,the increasedωvalues of Hox genes implied the relaxation of functional constraints of these genes during the mammalian evolutionary process.More importantly,49 positively-selected sites were identified in mammalian lineages with phenotypic modifications,indicating adaptive evolution acting on Hox genes and regulatory factors.In addition,3 parallel amino acid substitutions in some Hox genes were examined in marine mammals,which might be responsible for their streamlined body.
文摘The discovery of the homeobox motif and its presence in each gene of the Hox clusters revolutionized the fields of developmental biology and evolutionary developmental biology （1, 2）, providing a rapid entrance into investigating the mechanisms of development of almost any animal taxon as well as dramatically altering conceptions on the extent of genetic conservation across the animal kingdom.
文摘Archetypes of histone modifications associated with diverse chromosomal states that regulate access to DNA are leading the hypothesis of the histone code(or epigenetic code). However, it is still not evident how these post-translational modifications of histone tails lead to changes in chromatin structure. Histone modifications are able to activate and/or inactivate several genes and can be transmitted to next generation cells due to an epigenetic memory. The challenging issue is to identify or "decrypt" the code used to transmit these modifications to descent cells. Here, an attempt is made to describe how histone modifications operate as part of histone code that stipulates patterns of gene expression. This papers emphasizes particularly on the correlation between histone modifications and patterns of Hox gene expression in Caenorhabditis elegans. This work serves as an example to illustrate the power of the epigenetic machinery and its use in drug design and discovery.
文摘The three-dimensional(3D) organization of the eukaryotic genome is critical for its proper function. Evidence suggests that extensive chromatin loops form the building blocks of the genomic architecture, separating genes and gene clusters into distinct functional domains. These loops are anchored in part by a special type of DNA elements called chromatin boundary elements(CBEs). CBEs were originally found to insulate neighboring genes by blocking influences of transcriptional enhancers or the spread of silent chromatin. However, recent results show that chromatin loops can also play a positive role in gene regulation by looping out intervening DNA and "delivering" remote enhancers to gene promoters. In addition, studies from human and model organisms indicate that the configuration of chromatin loops, many of which are tethered by CBEs, is dynamically regulated during cell differentiation. In particular, a recent work by Li et al has shown that the SF1 boundary, located in the Drosophila Hox cluster, regulates local genes by tethering different subsets of chromatin loops: One subset enclose a neighboring gene ftz, limiting its access by the surrounding Scr enhancers and restrict the spread of repressive histones during early embryogenesis; and the other loops subdivide the Scr regulatory region into independent domains of enhancer accessibility. The enhancer-blocking activity of these CBE elements varies greatly in strength and tissue distribution. Further, tandem pairing of SF1 and SF2 facilitate the bypass of distal enhancers in transgenic flies, providing a mechanism for endogenous enhancers to circumvent genomic interruptions resulting from chromosomal rearrangement. This study demonstrates how a network of chromatin boundaries, centrally organized by SF1, can remodel the 3D genome to facilitate gene regulation during development.
