Ray, M.K., Wiskow, O., King, M.J., Ismail, N., Ergun, A., Wang, Y., Plys, A.J., Davis, C.P., Kathrein, K., Sadreyev, R., Borowsky, M.L., Eggan, K., Zon, L., Galloway, J.L., Kingston, R.E. (2016) CAT7 and cat7l long non-coding RNAs Tune Polycomb Repressive Complex 1 Function During Human and Zebrafish Development. The Journal of biological chemistry. 291(37):19558-72.
The essential functions of Polycomb Repressive Complex 1 (PRC1) in development and gene silencing are thought to involve long non-coding RNAs (lncRNAs), but few specific lncRNAs that guide PRC1 activity are known. We screened for lncRNAs which co-precipitate with PRC1 from chromatin and found candidates that impact Polycomb Group protein (PcG)-regulated gene expression in vivo. A novel lncRNA from this screen, CAT7, regulates expression and PcG binding at the MNX1 locus during early neuronal differentiation. CAT7 contains a unique tandem repeat domain which shares high sequence similarity to a non-syntenic zebrafish analog, cat7l. Defects caused by interference of cat7l RNA during zebrafish embryogenesis were rescued by human CAT7 RNA, enhanced by interference of a PRC1 component, and suppressed by interference of a known PRC1 target gene, demonstrating cat7l genetically interacts with a PRC1. We propose a model whereby PRC1 acts in concert with specific lncRNAs, and that CAT7/cat7l represent convergent lncRNAs that independently evolved to tune PRC1 repression at individual loci.