ROBNCA: robust network component analysis for recovering transcription factor activities.
BACKGROUND
Network component analysis (NCA) is an efficient method of reconstructing the transcription factor activity (TFA), which makes use of the gene expression data and prior information available about transcription factor (TF)-gene regulations. Most of the contemporary algorithms either exhibit the drawback of inconsistency and poor reliability, or suffer from prohibitive computational complexity. In addition, the existing algorithms do not possess the ability to counteract the presence of outliers in the microarray data. Hence, robust and computationally efficient algorithms are needed to enable practical applications.


RESULTS
We propose ROBust Network Component Analysis (ROBNCA), a novel iterative algorithm that explicitly models the possible outliers in the microarray data. An attractive feature of the ROBNCA algorithm is the derivation of a closed form solution for estimating the connectivity matrix, which was not available in prior contributions. The ROBNCA algorithm is compared with FastNCA and the non-iterative NCA (NI-NCA). ROBNCA estimates the TF activity profiles as well as the TF-gene control strength matrix with a much higher degree of accuracy than FastNCA and NI-NCA, irrespective of varying noise, correlation and/or amount of outliers in case of synthetic data. The ROBNCA algorithm is also tested on Saccharomyces cerevisiae data and Escherichia coli data, and it is observed to outperform the existing algorithms. The run time of the ROBNCA algorithm is comparable with that of FastNCA, and is hundreds of times faster than NI-NCA.


BACKGROUND
The ROBNCA software is available at http://people.tamu.edu/∼amina/ROBNCA
Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX 77843, USA, Corporate Research and Development, Qualcomm Technologies Inc., San Diego, CA 92121, USA, Department of Chemical Engineering and Department of Electrical Engineering, Texas A&M University at Qatar, Doha Qatar.
Amina
A
Noor
Aitzaz
A
Ahmad
Erchin
E
Serpedin
Mohamed
M
Nounou
Hazem
H
Nounou
D000465:Algorithms; D002453:Cell Cycle; D004926:Escherichia coli / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D016571:Neural Networks, Computer; D017711:Nonlinear Dynamics; D015203:Reproducibility of Results; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000032:analysis* / Q000235:genetics / Q000378:metabolism
D014157:Transcription Factors