Derepression of microRNA-mediated protein translation inhibition by apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G (APOBEC3G) and its family members.
The apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G (APOBEC3G or A3G) and its fellow cytidine deaminase family members are potent restrictive factors for human immunodeficiency virus type 1 (HIV-1) and many other retroviruses. A3G interacts with a vast spectrum of RNA-binding proteins and is located in processing bodies and stress granules. However, its cellular function remains to be further clarified. Using a luciferase reporter gene and green fluorescent protein reporter gene, we demonstrate that A3G and other APOBEC family members can counteract the inhibition of protein synthesis by various microRNAs (miRNAs) such as mir-10b, mir-16, mir-25, and let-7a. A3G could also enhance the expression level of miRNA-targeted mRNA. Further, A3G facilitated the association of microRNA-targeted mRNA with polysomes rather than with processing bodies. Intriguingly, experiments with a C288A/C291A A3G mutant indicated that this function of A3G is separable from its cytidine deaminase activity. Our findings suggest that the major cellular function of A3G, in addition to inhibiting the mobility of retrotransposons and replication of endogenous retroviruses, is most likely to prevent the decay of miRNA-targeted mRNA in processing bodies.
Huang
Jialing
J
Center for Human Virology, Division of Infectious Diseases, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
Liang
Zhihui
Z
Center for Human Virology, Division of Infectious Diseases, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
Yang
Bin
B
Center for Human Virology, Division of Infectious Diseases, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
Tian
Heng
H
Center for Human Virology, Division of Infectious Diseases, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
Ma
Jin
J
Center for Human Virology, Division of Infectious Diseases, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
Zhang
Hui
H
Center for Human Virology, Division of Infectious Diseases, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107. Electronic address: hui.zhang@jefferson.edu.
D000071480:APOBEC-3G Deaminase; D001055:Apolipoproteins B / Q000235:genetics*; D001483:Base Sequence; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism; D003564:Cytidine Deaminase / Q000737:chemistry / Q000378:metabolism*; D005434:Flow Cytometry; D017930:Genes, Reporter; D006801:Humans; D035683:MicroRNAs / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D009154:Mutation; D014176:Protein Biosynthesis; D016601:RNA-Binding Proteins / Q000737:chemistry; D012259:Ribonuclease, Pancreatic / Q000378:metabolism
D001055:Apolipoproteins B; D035683:MicroRNAs; D016601:RNA-Binding Proteins; D012259:Ribonuclease, Pancreatic; D000071480:APOBEC-3G Deaminase; C464924:APOBEC3G protein, human; D003564:Cytidine Deaminase