Bioinformatics Advance Access published online on February 28, 2008
Bioinformatics, doi:10.1093/bioinformatics/btn059
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Automated image alignment for 2-D gel electrophoresis in a high-throughput proteomics pipeline
1Institute of Biomedical Engineering, Imperial College London, United Kingdom.
2UCD Conway Institute of Biomolecular & Biomedical Research, University College Dublin, Ireland.
*To whom correspondence should be addressed. Guang-Zhong Yang, E-mail: g.z.yang{at}imperial.ac.uk
| Abstract |
|---|
Motivation: The quest for high-throughput proteomics has revealed a number of challenges in recent years. Whilst substantial improvements in automated protein separation with liquid chromatography and mass spectrometry (LC/MS), aka shotgun proteomics, have been achieved, large-scale open initiatives such as the HUPO Brain Proteome Project have shown that maximal proteome coverage is only possible when LC/MS is complemented by 2-D gel electrophoresis (2-DE) studies. Moreover, both separation methods require automated alignment and differential analysis to relieve the bioinformatics bottleneck and so make high-throughput protein biomarker discovery a reality. The purpose of this paper is to describe a fully automatic image alignment framework for the integration of 2-DE into a high-throughput differential expression proteomics pipeline.
Results: The proposed method is based on robust automated image normalisation (RAIN) to circumvent the drawbacks of traditional approaches. These use symbolic representation at the very early stages of the analysis, which introduces persistent errors due to inaccuracies in modelling and alignment. In RAIN, a 3rd order volume-invariant B-Spline spline model is incorporated into a multi-resolution schema to correct for geometric and expression inhomogeneity at multiple scales. The normalised images can then be compared directly in the image domain for quantitative differential analysis. Through evaluation against an existing state-of-the-art method on real and synthetically warped 2-D gels, the proposed analysis framework demonstrates substantial improvements in matching accuracy and differential sensitivity. High-throughput analysis is established through an accelerated GPGPU implementation.
Availability: Supplementary material, software and images used in the validation are available at http://www.proteomegrid.org/rain/.
Contact: g.z.yang{at}imperial.ac.uk
Received on September 11, 2007; revised on February 8, 2008; accepted on February 11, 2008