The post-transcriptional regulation of mRNA is a crucial component of gene expression.The disruption of this process has detrimental effects on the normal development and gives rise to various diseases.Searching for n...The post-transcriptional regulation of mRNA is a crucial component of gene expression.The disruption of this process has detrimental effects on the normal development and gives rise to various diseases.Searching for novel post-transcriptional regulators and exploring their roles are essential for understanding development and disease.Through a multimodal analysis of red blood cell trait genome-wide association studies(GWAS)and transcriptomes of erythropoiesis,we identify FAM46C,a non-canonical RNA poly(A)polymerase,as a necessary factor for proper red blood cell development.FAM46C is highly expressed in the late stages of the erythroid lineage,and its developmental upregulation is controlled by an erythroidspecific enhancer.We demonstrate that FAM46C stabilizes mRNA and regulates erythroid differentiation in a polymerase activity-dependent manner.Furthermore,we identify transcripts of lysosome and mitochondria components as highly confident in vivo targets of FAM46C,which aligns with the need of maturing red blood cells for substantial clearance of organelles and maintenance of cellular redox homeostasis.In conclusion,our study unveils a unique role of FAM46C in positively regulating lysosome and mitochondria components,thereby promoting erythropoiesis.展开更多
Background:Multiple myeloma(MM)is a hematologic malignancy characterized by the accumulation of aberrant plasma cells within the bone marrow.The high frequent mutation of family with sequence similarity 46,member C(FA...Background:Multiple myeloma(MM)is a hematologic malignancy characterized by the accumulation of aberrant plasma cells within the bone marrow.The high frequent mutation of family with sequence similarity 46,member C(FAM46C)is closely related with the occurrence and progression of MM.Recently,FAM46C has been identified as a non-canonical poly(A)polymerase(PAP)that functions as a tumor suppressor in MM.This study aimed to elucidate the structural features of this novel non-canonical PAP and how MM-related mutations affect the structural and biochemical properties of FAM46C,eventually advancing our understandings towards FAM46C mutation-related MM occurrence.Methods:We purified and crystallized a mammalian FAM46C construct,and solved its structure.Next,we characterized the property of FAM46C as a PAP through a combination of structural analysis,site-directed mutagenesis and biochemical assays,and by comparison with its homolog FAM46B.Finally,we structurally analyzed MM-related FAM46C mutations and tested the enzymatic activity of corresponding mutants.Results:We determined the crystal structure of a mammalian FAM46C protein at 2.35 A,and confirmed that FAM46C preferentially consumed adenosine triphosphate(ATP)and extended A-rich RNA substrates.FAM46C showed a weaker PAP activity than its homolog FAM46B,and this difference was largely dependent on the residue variance at particular sites.Of them,residues at positions 77,290,and 298 of mouse FAM46C weremost important for the divergence in enzymatic activity.Among the MM-associated FAM46C mutants,those residing at the catalytic site(D90G and D90H)or putative RNA-binding site(I155L,S156F,D182Y,F184L,Y247V,andM270V)showed abolished or compromised PAP activity of FAM46C,while N72A and S248A did not severely affect the PAP activity.FAM46C mutants D90G,D90H,I155L,S156F,F184L,Y247V,and M270V had significantly lower inhibitory effect on apoptosis of RPMI-8226 cells as compared to wild-type FAM46C.Conclusions:FAM46C is a prokaryotic-like PAP with preference forA-richRNA substrates,and showed distinct enzymatic efficiency with its homolog FAM46B.The MM-related missense mutations of FAM46C lead to various structural and biochemical outcomes to the protein.展开更多
基金funded by the Starting Fund from Zhejiang University to N.L.and grants to X.L.from National Natural Science Foundation of China(82170120 and 81670108)CAMS Initiative for Innovative Medicine(2017-12M-B&R-04)+2 种基金Medical Epigenetics Research Cen-ter,CAMS(2018PT31015)the State Key Laboratory of Medical Molecular Biology(2060204)Haihe L aboratory of Cell Ecosystem Innovation Fund(22HHXBSS00008).
文摘The post-transcriptional regulation of mRNA is a crucial component of gene expression.The disruption of this process has detrimental effects on the normal development and gives rise to various diseases.Searching for novel post-transcriptional regulators and exploring their roles are essential for understanding development and disease.Through a multimodal analysis of red blood cell trait genome-wide association studies(GWAS)and transcriptomes of erythropoiesis,we identify FAM46C,a non-canonical RNA poly(A)polymerase,as a necessary factor for proper red blood cell development.FAM46C is highly expressed in the late stages of the erythroid lineage,and its developmental upregulation is controlled by an erythroidspecific enhancer.We demonstrate that FAM46C stabilizes mRNA and regulates erythroid differentiation in a polymerase activity-dependent manner.Furthermore,we identify transcripts of lysosome and mitochondria components as highly confident in vivo targets of FAM46C,which aligns with the need of maturing red blood cells for substantial clearance of organelles and maintenance of cellular redox homeostasis.In conclusion,our study unveils a unique role of FAM46C in positively regulating lysosome and mitochondria components,thereby promoting erythropoiesis.
基金National Key R&D Program of China,Grant/Award Number:2018YFA0508300National Natural Science Foundation of China,Grant/Award Numbers:81772977,31722016,31470729+1 种基金Natural Science Foundation of Guangdong Province,Grant/Award Numbers:2019TX05Y598,2014TQ01R584,2014A030312015Innovative Team Program of Guangzhou Regenerative Medicine and Health Guangdong Laboratory,Grant/Award Number:2018GZR110103002。
文摘Background:Multiple myeloma(MM)is a hematologic malignancy characterized by the accumulation of aberrant plasma cells within the bone marrow.The high frequent mutation of family with sequence similarity 46,member C(FAM46C)is closely related with the occurrence and progression of MM.Recently,FAM46C has been identified as a non-canonical poly(A)polymerase(PAP)that functions as a tumor suppressor in MM.This study aimed to elucidate the structural features of this novel non-canonical PAP and how MM-related mutations affect the structural and biochemical properties of FAM46C,eventually advancing our understandings towards FAM46C mutation-related MM occurrence.Methods:We purified and crystallized a mammalian FAM46C construct,and solved its structure.Next,we characterized the property of FAM46C as a PAP through a combination of structural analysis,site-directed mutagenesis and biochemical assays,and by comparison with its homolog FAM46B.Finally,we structurally analyzed MM-related FAM46C mutations and tested the enzymatic activity of corresponding mutants.Results:We determined the crystal structure of a mammalian FAM46C protein at 2.35 A,and confirmed that FAM46C preferentially consumed adenosine triphosphate(ATP)and extended A-rich RNA substrates.FAM46C showed a weaker PAP activity than its homolog FAM46B,and this difference was largely dependent on the residue variance at particular sites.Of them,residues at positions 77,290,and 298 of mouse FAM46C weremost important for the divergence in enzymatic activity.Among the MM-associated FAM46C mutants,those residing at the catalytic site(D90G and D90H)or putative RNA-binding site(I155L,S156F,D182Y,F184L,Y247V,andM270V)showed abolished or compromised PAP activity of FAM46C,while N72A and S248A did not severely affect the PAP activity.FAM46C mutants D90G,D90H,I155L,S156F,F184L,Y247V,and M270V had significantly lower inhibitory effect on apoptosis of RPMI-8226 cells as compared to wild-type FAM46C.Conclusions:FAM46C is a prokaryotic-like PAP with preference forA-richRNA substrates,and showed distinct enzymatic efficiency with its homolog FAM46B.The MM-related missense mutations of FAM46C lead to various structural and biochemical outcomes to the protein.
