The lupus autoantigen La is an Xist -binding protein involved in Xist folding and cloud formation
Year: 2020
Type: preprint
Abstract: ABSTRACT Using the programmable RNA-sequence binding domain of the Pumilio protein, we FLAG-tagged Xist ( i nactivated X chromosome s pecific transcript) in live cells. Affinity pulldown coupled to mass spectrometry was employed to identify a list of 138 candidate Xist -binding proteins, from which, the lupus autoantigen La (encoding gene Ssb ) was validated as a protein functionally critical for X chromosome inactivation (XCI). Extensive XCI defects were detected in Ssb knockdown cells, including chromatin compaction, death of female ES cells during in vitro differentiation and chromosome-wide monoallelic gene expression pattern. Live-cell imaging of Xist RNA reveals the defining XCI defect: Xist cloud formation. La is a ubiquitous and versatile RNA-binding protein with RNA chaperone and RNA helicase activities. Functional dissection of La shows that the RNA chaperone domain and/or the ATP binding motif play critical roles in XCI. In mutant cells, Xist transcripts are unstable and misfolded. These results show that La is critically involved in XCI, possibly as a protein regulating the in-cell structure of Xist .
Authors: Norbert Ha, Nan Ding, Ru Hong, Rubing Liu, Xavier Roca, Yingyuan Luo, Xiaowei Duan, Xiao Wang, Peiling Ni, Li-Feng Zhang, Lingyi Chen
Language: English
Subfield: Genetics
Domain: Life Sciences
Open Access status: green
Funders: National Research Foundation, National Research Foundation Singapore, National Natural Science Foundation of China, Ministry of Education, India, Natural Science Foundation of Tianjin City, Higher Education Discipline Innovation Project, Medical Research Council, National Medical Research Council, Fundamental Research Funds for the Central Universities
OpenAlex ID: W3010338205