BioProspector

BioProspector identifies regulatory sequence motifs in upstream regions of genes that exhibit similar gene expression patterns using Gibbs sampling to reveal candidate regulatory elements.

Key Features:

• Gibbs Sampling Strategy: Employs a Gibbs sampling approach to probabilistically model and iteratively refine motif predictions, effective for co-regulated genes in prokaryotes and lower eukaryotes.
• C Implementation: Implemented as a C program for sequence scanning and motif discovery.
• Markov Background Models: Uses zero- to third-order Markov background models and can estimate model parameters from a specified sequence file or accept provided parameters.
• Motif Significance Assessment: Assesses motif significance via a motif score distribution derived through Monte Carlo methods to reduce false positives.
• Advanced Motif Modeling: Models gapped motifs and palindromic patterns to capture a broader range of regulatory element architectures.
• Comparative Genomics Integration: Can be complemented by CompareProspector to extend motif discovery to higher eukaryotes using comparative genomics.
• Output Formats: Produces position-specific probability matrices and reports individual motif sites and their locations on input sequences.

Scientific Applications:

• Transcription factor binding motif recovery: Demonstrated ability to recover binding motifs for Saccharomyces cerevisiae RAP1, Bacillus subtilis RNA polymerase, and Escherichia coli CRP.
• Regulatory element discovery in co-expressed genes: Applied to upstream regions of genes with similar expression patterns to identify candidate regulatory elements underlying coordinated expression.
• Comparative motif discovery: Extended to higher eukaryotes through integration with comparative genomics approaches (CompareProspector).

Methodology:

Computational methods explicitly include Gibbs sampling, zero- to third-order Markov background models (with parameter estimation from sequence files), Monte Carlo–derived motif score distributions, and modeling of gapped and palindromic motifs.