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Efficient Inference for Sparse Latent Variable Models of Transcriptional Regulation
Bioinformatics, 23:3776-3783, 2017.
Abstract
Motivation
Regulation of gene expression in prokaryotes involves complex
co-regulatory mechanisms involving large numbers of transcriptional
regulatory proteins and their target genes. Uncovering these
genome-scale interactions constitutes a major bottleneck in systems
biology. Sparse latent factor models, assuming activity of
transcription factors (TFs) as unobserved, provide a biologically
interpretable modelling framework, integrating gene expression and
genome-wide binding data, but at the same time pose a hard
computational inference problem. Existing probabilistic inference
methods for such models rely on subjective filtering and suffer from
scalability issues, thus are not well-suited for realistic
genome-scale applications.
Results
We present a fast Bayesian sparse factor model, which takes input
gene expression and binding sites data, either from ChIP-seq
experiments or motif predictions, and outputs active TF-gene links
as well as latent TF activities. Our method employs an efficient
variational Bayes scheme for model inference enabling its
application to large datasets which was not feasible with existing
MCMC-based inference methods for such models. We validate our method
on synthetic data against a similar model in the literature,
employing MCMC for inference, and obtain comparable results with a
small fraction of the computational time. We also apply our method
to large-scale data from Mycobacterium tuberculosis involving
ChIP-seq data on 113 TFs and matched gene expression data for 3863
putative target genes. We evaluate our predictions using an
independent transcriptomics experiment involving over-expression of
TFs.
Availability and implementation
An easy-to-use Jupyter notebook demo of our method with data is
available at https://github.com/zhenwendai/SITAR.
Supplementary information
Supplementary data are available at Bioinformatics online.