Co-expressed yeast genes cluster over a long range but are not regularly spaced

Area of Science:

• Genomics
• Molecular Biology
• Bioinformatics

Background:

• Gene expression can be influenced by genomic location.
• Previous studies using yeast arrays suggested spatial biases may affect expression profile analysis.
• Understanding gene co-expression domains is crucial for deciphering genome organization and function.

Purpose of the Study:

• To investigate the relationship between gene genomic position and expression profiles, independent of array spatial biases.
• To determine the size of co-expressed gene domains.
• To assess the evidence for expression periodicity and co-regulation periodicity across different genomes.

Main Methods:

• Analysis of spatially unbiased expression data from a large Northern blot study in yeast.
• Examination of gene co-expression patterns and domain sizes.
• Investigation of periodicity in gene expression and transcription factor binding data in yeast, human, and mouse genomes.

Main Results:

• Local domains of co-expressed genes in yeast extend up to 100 kb (approximately 30 genes), larger than previously thought.
• No evidence of expression profile periodicity was found in yeast.
• No convincing evidence for expression periodicity was observed in the human or mouse genomes.
• Analysis of yeast transcription factor binding data revealed no statistical evidence for chromosomal co-regulation periodicity.

Conclusions:

• Gene co-expression occurs in large local domains, challenging previous notions of smaller domains.
• The hypothesis of chromosomal periodicity in gene expression or co-regulation is not supported by current data in yeast, human, or mouse.
• Spatial biases in array printing can confound the interpretation of gene expression data related to genomic position.