title: The m subunit of murine translation initiation factor eIF3 maintains the integrity of the eIF3 complex and is required for embryonic development, homeostasis, and organ size control.
abstract: Mammalian eIF3 is composed of 13 subunits and is the largest eukaryotic initiation factor. eIF3 plays a key role in protein biosynthesis. However, it is not fully understood how different subunits contribute to the structural integrity and function of the eIF3 complex. Whether eIF3 is essential for embryonic development and homeostasis is also not known. Here, we show that eIF3m null embryos are lethal at the peri-implantation stage. Compound heterozygotes (eIF3m(flox)(/-)) or FABP4-Cre-mediated conditional knock-out mice are lethal at mid-gestation stages. Although the heterozygotes are viable, they show markedly reduced organ size and diminished body weight. Acute ablation of eIF3m in adult mouse liver leads to rapidly decreased body weight and death within 2 weeks; these effects are correlated with a severe decline of protein biogenesis in the liver. Protein analyses reveal that eIF3m deficiency significantly impairs the integrity of the eIF3 complex due to down-regulation of multiple other subunits. Two of the subunits, eIF3f and eIF3h, are stabilized by eIF3m through subcomplex formation. Therefore, eIF3m is required for the structural integrity and translation initiation function of eIF3. Furthermore, not only is eIF3m an essential gene, but its expression level is also important for mouse embryonic development and the control of organ size.
authors.affiliation: From the State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, and.
authors.forename: Liyong
authors.initials: L
authors.lastname: Zeng
authors.affiliation: From the State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, and.
authors.forename: Yihan
authors.initials: Y
authors.lastname: Wan
authors.affiliation: From the State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, and.
authors.forename: Dan
authors.initials: D
authors.lastname: Li
authors.affiliation: the Model Animal Research Center, Nanjing University, Nanjing, Jiangsu 210061, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Wu
authors.affiliation: the Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and.
authors.forename: Mengle
authors.initials: M
authors.lastname: Shao
authors.affiliation: the Model Animal Research Center, Nanjing University, Nanjing, Jiangsu 210061, China.
authors.forename: Jiong
authors.initials: J
authors.lastname: Chen
authors.affiliation: From the State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, and.
authors.forename: Lijian
authors.initials: L
authors.lastname: Hui
authors.affiliation: From the State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, and.
authors.forename: Hongbin
authors.initials: H
authors.lastname: Ji
authors.affiliation: From the State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, and. Electronic address: xlzhu@sibcb.ac.cn.
authors.forename: Xueliang
authors.initials: X
authors.lastname: Zhu
mesh_terms: D000818:Animals; D010064:Embryo Implantation / Q000502:physiology*; D039621:Eukaryotic Initiation Factor-3 / Q000096:biosynthesis* / Q000235:genetics; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D057809:HEK293 Cells; D006579:Heterozygote; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D008099:Liver; D051379:Mice; D018345:Mice, Knockout; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism*; D009929:Organ Size / Q000502:physiology; D014176:Protein Biosynthesis / Q000502:physiology*
chemical_list: D039621:Eukaryotic Initiation Factor-3; D046912:Multiprotein Complexes
keywords: Embryo; Eukaryotic Initiation Factor; Knock-out Mice; Mouse Genetics; Protein Complexes; Protein Stability; Translation Initiation Factors