Transcriptome-wide analysis of trypanosome mRNA decay reveals complex degradation kinetics and suggests a role for co-transcriptional degradation in determining mRNA levels

The SilicoTryp project aims at the creation of a “Silicon Trypanosome”, a comprehensive, experiment-based, multi-scale mathematical model of trypanosome physiology.
Trypanosomes are blood-stream parasites transmitted by tsetse flies; they cause African sleeping sickness in humans and livestock. Currently available drugs have severe side effects, and the parasites are rapidly developing resistance.
In this project, we collect a wide range of new experimental data on the parasite in its various
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Genes are transcribed in polysictronic messages (pre-mRNA) that are destined for either maturation into mRNAs, or degradation. Since transcription regulation is non-existent with few exceptions, the rate of pre-mRNA processing, together with mRNA decay and translation rates, are believed to control gene expression. In this assay, 2T1 blood form trypanosomes are subject to treatment by ActinomycinD for 5 minutes, inhibiting transcription. The cells are harvested, depleted for ribosomal RNA, and
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This assay is designed to measure the decay kinetics of mRNA in T. brucei blood forms. T. brucei lacks the canonical transcriptional regulation employed by other eukaryotes through transcription factors, and relies almost entirely on regulation of mRNA decay and further downstream steps in order to control gene expression.
3 replicates of 8 time points were taken to measure mRNA abundance in the cell using RNA-seq. The first time point was fot WT, untreated cells; the second was 5 min after the
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The RNAseq data on mRNA processing and mRNA decay were used to update a previously published model and to interrogate which process should be dependent on mRNA length

This files contains the parameter values, life-times, half-lives and errors associated with modeling the decay of the transcriptome, based on 3 models described in Deneke et al. "Complex degradation processes lead to non-exponential decay patters and age-dependent decay rates of messenger RNA". PLoS One. 2013;8(2):e55442

The file contains the normalized relative read counts (RPM) of 2 mRNA decay experiments. Columns in blue correspond to experiment 1, columns in violet correspond to experiment 2. The time points are in column headers. The last 3 columns contain parameters and half lives calculated from an exponantial fit of all data points. Normalization was done in 2 steps :first by calculating RPM i.e. reads per million of aligned reads to unique ORFs, second by normalizing this to the total amount of mRNA
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