Coding sequence and expression of the homeobox gene Hox 1.3

Area of Science:

• Developmental Biology
• Genetics
• Molecular Biology

Background:

• The Hox 1.3 gene, previously known as m2, is a murine homeobox-containing gene.
• It belongs to the Hox 1 gene cluster on chromosome 6.

Purpose of the Study:

• To characterize the murine Hox 1.3 gene, including its sequence, genomic organization, and expression during development.
• To investigate the relationship between Hox 1.3 expression and cellular transformation.

Main Methods:

• Isolation of a Hox 1.3 cDNA clone from a chemically transformed cell line library.
• Deduction of protein sequence and analysis of genomic structure (exons, introns).
• Analysis of Hox 1.3 expression in embryonic tissues and F9 cells during differentiation, and in 3T3 fibroblasts with varying transformation statuses.

Main Results:

• The Hox 1.3 protein (270 amino acids) shares homology with Hox 2.1, particularly in the homeodomain.
• Genomic organization involves two exons separated by a 960 bp intron.
• Maximal expression in 12-day embryonic tissue; two transcripts (1.9 kb and 4 kb) identified.
• Hox 1.3 expression is induced in F9 cells upon differentiation and negatively correlates with transformation in 3T3 fibroblasts.

Conclusions:

• Hox 1.3 is a distinct homeobox gene with conserved domains and specific expression patterns.
• Its expression is regulated during differentiation and suppressed in transformed cells, suggesting a role in development and tumor suppression.