Intracellular localization of human ZBP1: Differential regulation by the Z-DNA binding domain, Zalpha, in splice variants.
We investigated the subcellular distribution of human ZBP1, which harbors the N-terminal Z-DNA binding domains, Zalpha and Zbeta. ZBP1 was distributed primarily in the cytoplasm and occasionally as nuclear foci in interferon (IFN)-treated primary hepatocellular carcinoma cells, and in several other transfected cell types. In leptomycin B (LMB)-treated cells, endogenous ZBP1 efficiently accumulated in nuclear foci, which overlapped PML oncogenic domains (PODs) or nuclear bodies (NBs). In transfection assays, the unique C-terminal region of ZBP1 was necessary for its typical cytoplasmic localization. Interestingly, the Zalpha-deleted form displayed an increased association with PODs compared to wild-type and, unlike wild-type, perfectly accumulated in PODs in LMB-treated cells, implying that the presence of Zalpha domain also facilitates the cytoplasmic localization. Our results demonstrate that ZBP1 is localized primarily in the cytoplasm but also associated with nuclear PODs in IFN or LMB-treated cells. Given that about half of ZBP1 mRNA lacks exon 2 encoding the Zalpha domain, our data also suggest that the localization of ZBP1 may be differentially regulated by the Z-DNA binding domain, Zalpha, in splice variants.
Pham
Hong Thanh
HT
Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Sungkyunkwan University, Suwon, Republic of Korea.
Park
Mi-Young
MY
Kim
Kyeong Kyu
KK
Kim
Yang-Gyun
YG
Ahn
Jin-Hyun
JH
D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D001665:Binding Sites; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D002522:Chlorocebus aethiops; D003593:Cytoplasm / Q000378:metabolism; D043542:DNA, Z-Form / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology; D006023:Glycoproteins / Q000032:analysis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology; D008958:Models, Molecular; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012326:RNA Splicing; D016601:RNA-Binding Proteins; D014709:Vero Cells
D000903:Antibiotics, Antineoplastic; D043542:DNA, Z-Form; D004268:DNA-Binding Proteins; D005231:Fatty Acids, Unsaturated; D006023:Glycoproteins; D016601:RNA-Binding Proteins; C485731:ZBP1 protein, human; D007371:Interferon-gamma; C038753:leptomycin B