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Structure and expression pattern of the murine Hox-3.2 gene
J R Erselius1, M D Goulding, P Gruss
1Max-Planck-Institute of Biophysical Chemistry, Department of Molecular Cell Biology, Göttingen, FRG.
Development (Cambridge, England)
|October 1, 1990
Summary
The murine homeobox-containing gene Hox-3.2 is expressed in posterior embryonic regions and the ventral neural tube. Its distinct anterior expression boundary in the central nervous system and prevertebrae differs from paralogs.
Area of Science:
- Developmental Biology
- Genetics
- Molecular Biology
Background:
- The Hox-3 complex, located on chromosome 15, contains homeobox-containing genes crucial for embryonic development.
- Hox-3.2 is identified as the most 5' member of this complex.
- Homeobox genes typically possess a conserved hexapeptide, which is notably absent in the conceptual translation of Hox-3.2.
Purpose of the Study:
- To characterize the expression pattern of the murine homeobox-containing gene Hox-3.2 during embryonic development.
- To investigate the spatial and temporal distribution of Hox-3.2 transcripts.
- To compare the expression boundaries of Hox-3.2 with its paralogs in the central nervous system and prevertebrae.
Main Methods:
- Northern analysis to detect Hox-3.2 transcripts in embryonic samples.
- In situ hybridization to determine the precise localization of Hox-3.2 transcripts in developing embryos.
- Conceptual translation of the longest open reading frame (ORF) to analyze the protein structure.
Main Results:
- Northern analysis revealed three transcripts (1.5, 1.9, and 3.2 kb) in mouse embryos from day 9 to 15 post-coitum (p.c.).
- In situ hybridization detected Hox-3.2 transcripts in the posterior embryo by day 8.5 p.c., with expression in the ventral neural tube by day 10.5 p.c.
- A distinct anterior boundary of Hox-3.2 expression was observed at the level of the third thoracic prevertebra, remaining consistent through day 14.5 p.c. This gene was not expressed in dorsal horns containing sensory neurons, unlike Hox-3.1.
- Expression was also found in posterior prevertebrae, hindlimb buds, and the developing kidney cortex.
- Hox-3.2, along with Hox-2.5 and Hox-4.4 (5.2), exhibited notably different anterior expression boundaries in the central nervous system and prevertebrae compared to Hox-1.4 and Hox-1.3.
Conclusions:
- Hox-3.2 plays a role in the development of specific posterior embryonic structures, including the ventral neural tube, prevertebrae, and hindlimb buds.
- The gene's expression pattern, particularly its defined anterior boundary in the CNS and axial skeleton, suggests a specific role in patterning these regions.
- The unique expression profile of Hox-3.2, distinct from its paralogs, highlights the complex regulatory mechanisms governing Hox gene function during embryogenesis.