posted on 2023-02-02, 03:04authored byB Zhang, D Han, Y Korostelev, Zheng Yan, N Shao, E Khrameeva, BM Velichkovsky, Yi-Ping Phoebe ChenYi-Ping Phoebe Chen, MS Gelfand, P Khaitovich
Small nuclear and nucleolar RNAs (snRNAs and snoRNAs) are known to be functionally and evolutionarily conserved elements of transcript processing machinery. Here, we investigated the expression evolution of snRNAs and snoRNAs by measuring their abundance in the frontal cortex of humans, chimpanzees, rhesus monkeys, and mice. Although snRNA expression is largely conserved, 44% of the 185 measured snoRNA and 40% of the 134 snoRNA families showed significant expression divergence among species. The snRNA and snoRNA expression divergence included drastic changes unique to humans: A 10-fold elevated expression of U1 snRNA and a 1,000-fold drop in expression of SNORA29. The decreased expression of SNORA29 might be due to two mutations that affect secondary structure stability. Using in situ hybridization, we further localized SNORA29 expression to nucleolar regions of neuronal cells. Our study presents the first observation of snoRNA abundance changes specific to the human lineage and suggests a possible mechanism underlying these changes.
Funding
This work was supported by CAS Strategic Priority Research Program (grant no. XDB13010200); National Natural Science Foundation of China (grant nos. 91331203, 31420103920, 31501047); Bureau of International Cooperation, Chinese Academy of Sciences (grant no. GJHZ201313); Foreign Expert 1000 Talents Plan Program (grant no. WQ20123100078 to P.K.); Russian Science Foundation (grant 14-28-00234 to N.R.C. "Kurchatov Institite"); and China Postdoctoral Science Foundation (grant no. 2015M571610 to H.D.D.).