Gaussian Process Modelling of Latent Chemical Species: Applications to Inferring Transcription Factor Activities
Abstract
Motivation: Inference of latent chemical species in
biochemical interaction networks is a key problem in estimation of
the structure and parameters of the genetic, metabolic and protein
interaction networks that underpin all biological processes. We
present a framework for Bayesian marginalisation of these latent
chemical species through Gaussian process priors.
Results: We demonstrate our general approach on three
different biological examples of single input motifs, including both
activation and repression of transcription. We focus in particular
on the problem of inferring transcription factor activity when the
concentration of active protein cannot easily be measured. We show
how the uncertainty in the inferred transcription factor activity
can be integrated out in order to derive a likelihood function that
can be used for the estimation of regulatory model parameters. An
advantage of our approach is that we avoid the use of a
coarse-grained discretization of continuous-time functions, which
would lead to a large number of additional parameters to be
estimated. We develop efficient exact and approximate inference
schemes, which are much more efficient than competing sampling-based
schemes and therefore provide us with a practical toolkit for
model-based inference.
Availability: The software and data for recreating all the
experiments in this paper is available in MATLAB from
http://inverseprobability.com/gpsim
Contact: Neil Lawrence