Comprehensive comparative homeobox gene annotation in human and mouse.

Area of Science:

• Genomics
• Developmental Biology
• Transcriptomics

Background:

• Homeobox genes are crucial transcription factors regulating embryonic pattern formation.
• These genes often form clusters, with some associated with regulatory long non-coding RNAs (lncRNAs).
• Automated gene annotation methods face challenges with accuracy, especially for complex gene clusters and non-coding elements.

Purpose of the Study:

• To perform a comprehensive manual annotation of all homeobox genes and their associated antisense lncRNAs in human and mouse genomes.
• To identify discrepancies in existing annotations and update gene structures, biotypes, and nomenclature.
• To compare the prevalence of antisense lncRNAs associated with homeobox genes between humans and mice.

Main Methods:

• Manual annotation of all homeobox genes, including splice variants and pseudogenes, in human and mouse genomes.
• Identification and annotation of antisense and flanking lncRNAs.
• Comparative analysis of annotated homeobox gene clusters and their associated lncRNAs between species.
• Utilizing publicly available transcriptional evidence for validation.

Main Results:

• Identified discrepancies in current RefSeq annotations regarding gene structures and locus biotypes.
• Discovered and annotated previously un-identified pseudogenes in the DUX, Rhox, and Obox gene clusters, leading to updated nomenclature.
• Found a significantly higher enrichment of antisense lncRNA loci associated with human homeobox genes (41%) compared to mouse orthologues (22%).

Conclusions:

• Manual annotation provides a more accurate representation of homeobox gene clusters and their regulatory elements.
• Human homeobox genes exhibit a greater association with antisense lncRNAs, suggesting potential species-specific regulatory mechanisms.
• Updated annotations and nomenclature facilitate future research into homeobox gene function and regulation.