STAG-CNS

STAG-CNS identifies conserved noncoding regulatory regions (CNSs) by comparative analysis of promoters of orthologous genes from three or more species to map conserved regulatory elements in plant genomes.

Key Features:

• Multi-species integration: Analyzes data from up to six grass species to detect conserved noncoding sequences across multiple genomes.
• Promoter-focused comparative analysis: Compares promoters of orthologous genes from three or more species to pinpoint conserved regulatory regions.
• Short-sequence sensitivity: Identifies conserved sequences as short as 9 base pairs (bp), whereas most existing methods require ≥15 bp.
• Divergence rate quantification: Quantifies rates of sequence divergence between related species to distinguish putatively functional from non-functional sequences.
• False discovery rate control: Maintains a stringent false discovery rate (FDR) threshold of ≤0.05 for identified CNSs.
• Open chromatin overlap assessment: Evaluates overlap of identified CNSs with open chromatin regions defined by DNase I hypersensitivity assays.
• Regulatory promoter enrichment: Detects enrichment of CNSs in promoters of genes involved in transcriptional regulation.

Scientific Applications:

• Characterization of gene regulation: Mapping CNSs and short conserved elements to aid identification of transcription factor binding sites and other regulatory elements.
• Study of polyploidy events: Analysis of loss of conserved noncoding sequences associated with retained duplicate genes from ancient polyploidy events, exemplified by maize.
• Expression context analysis: Correlating number of retained CNSs with overall gene expression, showing genes with fewer retained CNSs exhibit lower expression particularly in complex organs with diverse cell types, implying reduced numbers of expression contexts.

Methodology:

Integrates comparative genomic data from up to six grass species, compares promoters of orthologous genes from three or more species, identifies conserved sequences down to 9 bp, quantifies sequence divergence rates, applies FDR ≤0.05, assesses overlap with DNase I hypersensitivity data, and performs enrichment analysis in promoters of transcriptional regulator genes.