PAX6 intronic sequence targets expression to the spinal cord

Area of Science:

• Developmental Biology
• Genetics
• Molecular Biology

Background:

• The PAX6 gene, a member of the paired-box and homeobox family, is crucial for development and exhibits high conservation across species at both protein and DNA levels.
• A specific 216-base pair sequence in intron 4 of the Pax6 gene was identified as conserved among human, mouse, and quail.

Purpose of the Study:

• To investigate the functional role of the conserved 216-bp Pax6 intron 4 sequence.
• To determine if this conserved sequence acts as a transcriptional enhancer in vivo.
• To assess the conservation of PAX6 at the transcriptional level.

Main Methods:

• Transgenic mice were created using a construct containing the human PAX6 promoter linked to the conserved human 216-bp intron 4 sequence (ele4H).
• Expression of the lacZ reporter gene was analyzed in the spinal cords of these transgenic mice.
• Comparative analysis of sequence conservation across human, mouse, and quail was performed.

Main Results:

• The human 216-bp conserved sequence (ele4H), when driven by the human PAX6 promoter, functioned as a spinal cord-specific enhancer in transgenic mice.
• This enhancer element (ele4H) specifically drove lacZ expression in the thoracic and lumbar regions of the spinal cord.
• The enhancer activity was dependent on the presence of a functional PAX6 promoter.

Conclusions:

• The conserved Pax6 intron 4 sequence (ele4H) acts as a functional enhancer element regulating gene expression in the spinal cord.
• These findings demonstrate that PAX6 is conserved not only functionally but also at the transcriptional regulatory level.
• This study provides insights into the regulatory mechanisms of PAX6 during development.