Sequence structures of a mouse major urinary protein gene and pseudogene compared

Area of Science:

• Genomics
• Molecular Biology
• Mammalian Genetics

Background:

• Mice possess approximately 35 major urinary protein (MUP) genes, clustered on chromosome 4, primarily in two groups.
• Group 1 MUP genes are considered active, while Group 2 genes are presumed pseudogenes.

Purpose of the Study:

• To present the complete sequence of active (Group 1) and pseudogene (Group 2) MUP genes.
• To identify sequence differences that may explain differential gene expression and mRNA splicing.

Main Methods:

• Complete gene sequencing of a Group 1 and a Group 2 MUP gene.
• Analysis of 700 bp of flanking sequence for both genes.
• Comparison of gene sequences, including regulatory elements and coding regions.

Main Results:

• The Group 1 gene sequence is consistent with active transcription.
• The Group 2 gene contains mutations (stop codons, frame-shift) rendering it a pseudogene in the context of Group 1.
• Sequence variations in the Group 2 gene include deletions, base changes, and altered regulatory signals, potentially affecting mRNA levels and splicing.

Conclusions:

• The identified mutations confirm the Group 2 MUP gene as a pseudogene.
• Sequence differences likely contribute to the 10- to 20-fold higher Group 1 mRNA levels in mouse liver.
• Despite pseudogene status, Group 2 MUPs may retain biological activity through their encoded hexapeptide.