The specification of germ cells in zebrafish mostly relies on an inherited mechanism by which localized maternal determinants,called germ plasm,confer germline fate in the early embryo.Extensive studies have partially...The specification of germ cells in zebrafish mostly relies on an inherited mechanism by which localized maternal determinants,called germ plasm,confer germline fate in the early embryo.Extensive studies have partially allowed the identification of key regulators governing germ plasm formation and subsequent germ cell development.RNA-binding proteins,acting in concert with other germ plasm components,play essential roles in the organization of the germ plasm and the specification,migration,maintenance,and differentiation of primordial germ cells.The loss of their functions impairs germ cell formation and causes sterility or sexual conversion.Evidence is emerging that they instruct germline development through differential regulation of mRNA fates in somatic and germ cells.However,the challenge remains to decipher the complex interplay of maternal germ plasm components in germ plasm compartmentalization and germ cell specification.Because failure to control the developmental outcome of germ cells disrupts the formation of gametes,it is important to gain a complete picture of regulatory mechanisms operating in the germ cell lineage.This review sheds light on the contributions of RNA-binding proteins to germ cell development in zebrafish and highlights intriguing questions that remain open for future investigation.展开更多
Upon recognition of foreign antigens,naïve B cells undergo rapid activation,growth,and proliferation.How B-cell growth and proliferation are coupled with activation remains poorly understood.Combining CRISPR/Cas9...Upon recognition of foreign antigens,naïve B cells undergo rapid activation,growth,and proliferation.How B-cell growth and proliferation are coupled with activation remains poorly understood.Combining CRISPR/Cas9-mediated functional analysis and mouse genetics approaches,we found that Dhx33,an activation-induced RNA helicase,plays a critical role in coupling B-cell activation with growth and proliferation.Mutant mice with B-cell-specific deletion of Dhx33 exhibited impaired B-cell development,germinal center reactions,plasma cell differentiation,and antibody production.Dhx33-deficient B cells appeared normal in the steady state and early stage of activation but were retarded in growth and proliferation.Mechanistically,Dhx33 played an indispensable role in activation-induced upregulation of ribosomal DNA(rDNA)transcription.In the absence of Dhx33,activated B cells were compromised in their ability to ramp up 47S ribosomal RNA(rRNA)production and ribosome biogenesis,resulting in nucleolar stress,p53 accumulation,and cellular death.Our findings demonstrate an essential role for Dhx33 in coupling B-cell activation with growth and proliferation and suggest that Dhx33 inhibition is a potential therapy for lymphoma and antibody-mediated autoimmune diseases.展开更多
文摘The specification of germ cells in zebrafish mostly relies on an inherited mechanism by which localized maternal determinants,called germ plasm,confer germline fate in the early embryo.Extensive studies have partially allowed the identification of key regulators governing germ plasm formation and subsequent germ cell development.RNA-binding proteins,acting in concert with other germ plasm components,play essential roles in the organization of the germ plasm and the specification,migration,maintenance,and differentiation of primordial germ cells.The loss of their functions impairs germ cell formation and causes sterility or sexual conversion.Evidence is emerging that they instruct germline development through differential regulation of mRNA fates in somatic and germ cells.However,the challenge remains to decipher the complex interplay of maternal germ plasm components in germ plasm compartmentalization and germ cell specification.Because failure to control the developmental outcome of germ cells disrupts the formation of gametes,it is important to gain a complete picture of regulatory mechanisms operating in the germ cell lineage.This review sheds light on the contributions of RNA-binding proteins to germ cell development in zebrafish and highlights intriguing questions that remain open for future investigation.
基金the National Natural Science Foundation of China(31570882,31770950 and 32070877 to W-H.L,and 81961138008 to CX)the Fundamental Research Funds for the Central Universities of China-Xiamen University(20720170064 to CX)the Sanofi Institute for Biomedical Research(SIBR).
文摘Upon recognition of foreign antigens,naïve B cells undergo rapid activation,growth,and proliferation.How B-cell growth and proliferation are coupled with activation remains poorly understood.Combining CRISPR/Cas9-mediated functional analysis and mouse genetics approaches,we found that Dhx33,an activation-induced RNA helicase,plays a critical role in coupling B-cell activation with growth and proliferation.Mutant mice with B-cell-specific deletion of Dhx33 exhibited impaired B-cell development,germinal center reactions,plasma cell differentiation,and antibody production.Dhx33-deficient B cells appeared normal in the steady state and early stage of activation but were retarded in growth and proliferation.Mechanistically,Dhx33 played an indispensable role in activation-induced upregulation of ribosomal DNA(rDNA)transcription.In the absence of Dhx33,activated B cells were compromised in their ability to ramp up 47S ribosomal RNA(rRNA)production and ribosome biogenesis,resulting in nucleolar stress,p53 accumulation,and cellular death.Our findings demonstrate an essential role for Dhx33 in coupling B-cell activation with growth and proliferation and suggest that Dhx33 inhibition is a potential therapy for lymphoma and antibody-mediated autoimmune diseases.
