Fig. 1: Extraordinarily high levels of splicing occur at the active VSG ES, which is necessary for its transcription.
From: An assembly of nuclear bodies associates with the active VSG expression site in African trypanosomes
a Estimated mRNA transcripts produced per hour from an active VSG gene, an average of all Pol II-transcribed genes (Pol II), or a tubulin gene (Tub) in bloodstream form (BF) T. brucei. This is compared with mRNA from a procyclin (EP or GPEET) gene in procyclic form (PF) T. brucei. b Estimated difference in splicing rate (fold difference) at the active VSG gene or an average ES gene (BES) compared with an average of all Pol II-transcribed genes. The data used to calculate the values presented in panels (a, b) are shown in Supplementary Tables 1 and 2. c Representative fluorescence microscopy images of RNA-FISH detecting the U2 snRNA (green) or VSG pseudogene (Ψ) transcript (magenta) specific for BES1 in BF T. brucei cells. The nucleus is indicated with a dashed line, scale bar = 1 μm. A line profile displaying the U2 snRNA and VSGΨ signal intensities is shown, with fluorescence indicated in arbitrary units (arb. units). d Quantitation of the percentage (%) of cells with MS2 RNA-FISH signal in cells with different genomic loci marked with MS2 repeats, at different time points in minutes (min) after transfection with anti-U2 snRNA Morpholinos. Minimally 300 G1 (1K1N) cells were counted per time point. Values shown are the average of three biological replicates, error bars indicate ± SD. e Fluorescence microscopy imaging of a BF T. brucei cell line expressing mNG::RPA2 (green) treated with sinefungin. Time is indicated in minutes (min). The nucleus (dashed line) is stained with DAPI (blue), and the ESB indicated with a white arrowhead. Scale bar = 1 μm. f Quantitation of the percentage of cells with an ESB in the cell line shown in (e) after treatment with sinefungin. Values do not add up to 100%, as not all cells had a detectable ESB. Average values for three biological replicates are shown. At least 200 G1 (1K1N) cells were counted per time point with error bars indicating ± SD. P values were determined using a two-tailed paired Student’s t test. *P = 0.0168. Source data are provided as a Source Data file.
