TY - JOUR
T1 - Real-time visualization of ZBP1 association with β-actin mRNA during transcription and localization
AU - Oleynikov, Yuri
AU - Singer, Robert H.
N1 - Funding Information:
This work was supported by National Institutes of Health grant AR41480. We thank Shailesh M. Shenoy for his essential expertise in imaging and processing the data. We also thank Carolyn Marks and the Analytical Imaging Facility at Albert Einstein College of Medicine for expert electron microscopy assistance.
PY - 2003/2
Y1 - 2003/2
N2 - Background: mRNA localization in somatic cells is an important mechanism for gene expression regulation. In fibroblasts, the protein ZBP1 associates with the sequence that localizes β-actin mRNA to the leading edge of fibroblasts, augmenting motility. β-actin mRNA localizes in a cytoskeleton-dependent manner, depending on intact actin and myosin ATP-hydrolysis, and is largely bound to the actin cytoskeleton. The ZBP1 protein contains four KH RNA binding domains and a classic RBD RNA binding domain. It also contains a putative nuclear import and export sequence, suggesting a nuclear phase in this protein's function. Results: Using high-speed imaging, we show here the targeting of this RNA binding protein to β-actin pre-mRNA transcripts in the nuclei of living cells and measure the residence time of the RNA-protein complex before it leaves the transcription site. Then, the RNA-protein particle is exported to the cytoplasm, where it localizes at velocities of 0.6 μm/s by using actin filaments and/or microtubules. This RNA-ZBP1 complex is required for cytoplasmic localization in fibroblasts; mislocalizing the protein also mislocalizes the RNA, and expressing the protein in a ZBP1-deficient cell line induces β-actin mRNA localization. Conclusions: This work demonstrates that the RNA-protein association, essential for cytoplasmic localization, begins as soon as the RNA is transcribed. The ZBP1 then forms a ribonucleoprotein particle and moves in a myosin-dependent fashion by using the cytoskeleton for directional transport.
AB - Background: mRNA localization in somatic cells is an important mechanism for gene expression regulation. In fibroblasts, the protein ZBP1 associates with the sequence that localizes β-actin mRNA to the leading edge of fibroblasts, augmenting motility. β-actin mRNA localizes in a cytoskeleton-dependent manner, depending on intact actin and myosin ATP-hydrolysis, and is largely bound to the actin cytoskeleton. The ZBP1 protein contains four KH RNA binding domains and a classic RBD RNA binding domain. It also contains a putative nuclear import and export sequence, suggesting a nuclear phase in this protein's function. Results: Using high-speed imaging, we show here the targeting of this RNA binding protein to β-actin pre-mRNA transcripts in the nuclei of living cells and measure the residence time of the RNA-protein complex before it leaves the transcription site. Then, the RNA-protein particle is exported to the cytoplasm, where it localizes at velocities of 0.6 μm/s by using actin filaments and/or microtubules. This RNA-ZBP1 complex is required for cytoplasmic localization in fibroblasts; mislocalizing the protein also mislocalizes the RNA, and expressing the protein in a ZBP1-deficient cell line induces β-actin mRNA localization. Conclusions: This work demonstrates that the RNA-protein association, essential for cytoplasmic localization, begins as soon as the RNA is transcribed. The ZBP1 then forms a ribonucleoprotein particle and moves in a myosin-dependent fashion by using the cytoskeleton for directional transport.
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U2 - 10.1016/S0960-9822(03)00044-7
DO - 10.1016/S0960-9822(03)00044-7
M3 - Article
C2 - 12573215
AN - SCOPUS:0037314639
SN - 0960-9822
VL - 13
SP - 199
EP - 207
JO - Current Biology
JF - Current Biology
IS - 3
ER -