The human XPG gene: gene architecture, alternative splicing and single nucleotide polymorphisms

Area of Science:

• Genetics
• Molecular Biology
• Genomic Medicine

Background:

• Defects in the XPG DNA repair endonuclease gene are linked to cancer-prone disorders like xeroderma pigmentosum (XP).
• Understanding the genomic sequence of the XPG gene is crucial for elucidating its diverse functions.
• Previous knowledge was limited to the XPG cDNA sequence.

Purpose of the Study:

• To determine the genomic sequence of the human XPG gene.
• To analyze splice sites and identify alternatively spliced XPG mRNA isoforms.
• To investigate the implications of alternative splicing in XPG gene function and associated disorders.

Main Methods:

• Determined the 30 kb genomic sequence of the human XPG gene, comprising 15 exons and 14 introns.
• Analyzed splice donor and acceptor sites using an information theory-based approach.
• Identified alternatively spliced XPG mRNA isoforms in normal and patient cells using molecular techniques.

Main Results:

• The human XPG gene spans 30 kb with 15 exons and 14 introns.
• Identified six alternatively spliced XPG mRNA isoforms, including partial exon deletions, intron retentions, and alternative exons.
• Discovered that alternative splicing patterns vary across different tissues and identified specific splice sites associated with the minor (U12) spliceosome.

Conclusions:

• The human XPG gene exhibits complex alternative splicing patterns, influenced by multiple low-information content splice sites.
• Alternative splicing of XPG mRNA isoforms may contribute to the diverse functions of the gene and its role in disease.
• Further research into XPG alternative splicing is warranted to understand its impact on DNA repair and cancer predisposition.