Identification of a 35S U4/U6.U5 tri-small nuclear ribonucleoprotein (tri-snRNP) complex intermediate in spliceosome assembly.

Zhe Chen, Bin Gui, Yu Zhang, Guojia Xie, Wanjin Li, Shumeng Liu, Bosen Xu, Chongyang Wu, Lin He, Jianguo Yang, Xia Yi, Xiaohan Yang, Luyang Sun, Jing Liang, Yongfeng Shang

The Journal of biological chemistry 2017 Nov 03

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The de novo assembly and post-splicing reassembly of the U4/U6.U5 tri-snRNP remain to be investigated. We report here that ZIP, a protein containing a CCCH-type zinc finger and a G-patch domain, as characterized by us previously, regulates pre-mRNA splicing independent of RNA binding. We found that ZIP physically associates with the U4/U6.U5 tri-small nuclear ribonucleoprotein (tri-snRNP). Remarkably, the ZIP-containing tri-snRNP, which has a sedimentation coefficient of ∼35S, is a tri-snRNP that has not been described previously. We also found that the 35S tri-snRNP contains hPrp24, indicative of a state in which the U4/U6 di-snRNP is integrating with the U5 snRNP. We found that the 35S tri-snRNP is enriched in the Cajal body, indicating that it is an assembly intermediate during 25S tri-snRNP maturation. We showed that the 35S tri-snRNP also contains hPrp43, in which ATPase/RNA helicase activities are stimulated by ZIP. Our study identified, for the first time, a tri-snRNP intermediate, shedding new light on the de novo assembly and recycling of the U4/U6.U5 tri-snRNP. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Citation

Zhe Chen, Bin Gui, Yu Zhang, Guojia Xie, Wanjin Li, Shumeng Liu, Bosen Xu, Chongyang Wu, Lin He, Jianguo Yang, Xia Yi, Xiaohan Yang, Luyang Sun, Jing Liang, Yongfeng Shang. Identification of a 35S U4/U6.U5 tri-small nuclear ribonucleoprotein (tri-snRNP) complex intermediate in spliceosome assembly. The Journal of biological chemistry. 2017 Nov 03;292(44):18113-18128