Cilia are microtubule-based organelles projecting from the cell surface with important sensory and motility functions.Ciliary defects are associated with diverse diseases collectively known as ciliopathies.However,the...Cilia are microtubule-based organelles projecting from the cell surface with important sensory and motility functions.Ciliary defects are associated with diverse diseases collectively known as ciliopathies.However,the molecular mechanisms that govern ciliogenesis remain not fully understood.Here,we demonstrate that ubiquitin-specific protease 21(USP21)is indispensable for cilium formation through its deubiquitinating activity.Usp21 knockout mice exhibit ciliary defects in multiple organs,such as the kidney,liver,and trachea.Our data also reveal a constant localization of USP21 at the centrosome and basal body during ciliogenesis.Mechanistically,USP21 interacts with dihydropyrimidinase-like 2(DPYSL2)at the centrosome and removes lysine 48-linked ubiquitination from DPYSL2.Loss of USP21 leads to the proteasomal degradation of DPYSL2 and causes a significant reduction in its centrosome abundance,ultimately resulting in ciliary defects.These findings thus identify a critical role for the USP21–DPYSL2 axis in ciliogenesis and have important implications for health and disease.展开更多
Background and Aims:General transcription factor IIIC subunit 2(GTF3C2)is one of the polymerase III transcription-related factors.Previous studies have revealed that GTF3C2 is involved in regulating cell proliferation...Background and Aims:General transcription factor IIIC subunit 2(GTF3C2)is one of the polymerase III transcription-related factors.Previous studies have revealed that GTF3C2 is involved in regulating cell proliferation.However,the role of GTF3C2 in hepatocellular carcinoma(HCC)remains un-clear.This study aimed to determine its expression,biologi-cal function,and mechanism in HCC.Methods:The expres-sion of GTF3C2 in HCC and non-tumor tissues,along with its clinical significance,was investigated using public databases and clinical samples.Reverse transcription-quantitative poly-merase chain reaction and Western blot assays were per-formed to detect the expression of GTF3C2,ubiquitin specific peptidase 21(USP21),mitogen-activated protein kinase 2(MEK2),extracellular signal-regulated kinase 1/2(ERK1/2),and p-ERK1/2 in cells.A luciferase reporter assay was con-ducted to explore the regulatory effect of GTF3C2 on USP21 transcription.Cell Counting Kit-8,5-ethynyl-2′-deoxyuridine,and colony formation assays were performed to assess HCC cell proliferation.Subcutaneous injection of HCC cells into nude mice was used to evaluate tumor growth in vivo.Re-sults:GTF3C2 expression was upregulated in HCC tissues and was positively correlated with advanced tumor stages and high tumor grades.HCC patients with high GTF3C2 ex-pression had significantly worse survival outcomes.Knock-down of GTF3C2 suppressed the proliferation of Hep3B and HCCLM3 cells,while overexpression of GTF3C2 facilitated the proliferation of SNU449 and Huh7 cells.GTF3C2 promoted USP21 expression by activating its transcription,which sub-sequently increased the levels of MEK2 and p-ERK1/2 in HCC cells.Overexpression of both USP21 and MEK2 counteracted the GTF3C2 knockdown-induced inactivation of the ERK1/2 pathway.Moreover,GTF3C2 promoted HCC cell proliferation in vitro and tumor growth in vivo by regulating the USP21/MEK2/ERK1/2 pathway.Conclusions:Upregulation of GT-F3C2 is frequently observed in HCC tissues and predicts poor prognosis.GTF3C2 promotes HCC cell proliferation via the USP21/MEK2/ERK1/2 pathway.展开更多
基金supported by the National Natural Science Foundation of China(32300694,32270807,32170829,and 31900538)the Shandong Natural Science Foundation(2022HWYQ-075)the Taishan Scholar Foundation of Shandong Province(tsqn202211109).
文摘Cilia are microtubule-based organelles projecting from the cell surface with important sensory and motility functions.Ciliary defects are associated with diverse diseases collectively known as ciliopathies.However,the molecular mechanisms that govern ciliogenesis remain not fully understood.Here,we demonstrate that ubiquitin-specific protease 21(USP21)is indispensable for cilium formation through its deubiquitinating activity.Usp21 knockout mice exhibit ciliary defects in multiple organs,such as the kidney,liver,and trachea.Our data also reveal a constant localization of USP21 at the centrosome and basal body during ciliogenesis.Mechanistically,USP21 interacts with dihydropyrimidinase-like 2(DPYSL2)at the centrosome and removes lysine 48-linked ubiquitination from DPYSL2.Loss of USP21 leads to the proteasomal degradation of DPYSL2 and causes a significant reduction in its centrosome abundance,ultimately resulting in ciliary defects.These findings thus identify a critical role for the USP21–DPYSL2 axis in ciliogenesis and have important implications for health and disease.
基金supported by a grant from the Huadong Medicine Joint Funds of the Zhejiang Provincial Natural Science Foundation of China(Grant No.LHDMD23H300002).
文摘Background and Aims:General transcription factor IIIC subunit 2(GTF3C2)is one of the polymerase III transcription-related factors.Previous studies have revealed that GTF3C2 is involved in regulating cell proliferation.However,the role of GTF3C2 in hepatocellular carcinoma(HCC)remains un-clear.This study aimed to determine its expression,biologi-cal function,and mechanism in HCC.Methods:The expres-sion of GTF3C2 in HCC and non-tumor tissues,along with its clinical significance,was investigated using public databases and clinical samples.Reverse transcription-quantitative poly-merase chain reaction and Western blot assays were per-formed to detect the expression of GTF3C2,ubiquitin specific peptidase 21(USP21),mitogen-activated protein kinase 2(MEK2),extracellular signal-regulated kinase 1/2(ERK1/2),and p-ERK1/2 in cells.A luciferase reporter assay was con-ducted to explore the regulatory effect of GTF3C2 on USP21 transcription.Cell Counting Kit-8,5-ethynyl-2′-deoxyuridine,and colony formation assays were performed to assess HCC cell proliferation.Subcutaneous injection of HCC cells into nude mice was used to evaluate tumor growth in vivo.Re-sults:GTF3C2 expression was upregulated in HCC tissues and was positively correlated with advanced tumor stages and high tumor grades.HCC patients with high GTF3C2 ex-pression had significantly worse survival outcomes.Knock-down of GTF3C2 suppressed the proliferation of Hep3B and HCCLM3 cells,while overexpression of GTF3C2 facilitated the proliferation of SNU449 and Huh7 cells.GTF3C2 promoted USP21 expression by activating its transcription,which sub-sequently increased the levels of MEK2 and p-ERK1/2 in HCC cells.Overexpression of both USP21 and MEK2 counteracted the GTF3C2 knockdown-induced inactivation of the ERK1/2 pathway.Moreover,GTF3C2 promoted HCC cell proliferation in vitro and tumor growth in vivo by regulating the USP21/MEK2/ERK1/2 pathway.Conclusions:Upregulation of GT-F3C2 is frequently observed in HCC tissues and predicts poor prognosis.GTF3C2 promotes HCC cell proliferation via the USP21/MEK2/ERK1/2 pathway.
