Targeted disruption of Hoxd-10 affects mouse hindlimb development

Area of Science:

• Developmental biology
• Genetics
• Neuroscience

Background:

• The HoxD gene cluster is essential for limb development.
• Hoxd-10 is a key gene within the HoxD cluster, located at the 5' end.
• Its precise role in hindlimb development and associated neural patterning is not fully understood.

Purpose of the Study:

• To investigate the functional role of the Hoxd-10 gene in hindlimb development and locomotion.
• To identify the specific skeletal, muscular, and neural abnormalities resulting from Hoxd-10 gene disruption.
• To elucidate the contribution of Hoxd-10 to spinal cord regional identity.

Main Methods:

• Generation of mutant mice with targeted disruption of the Hoxd-10 gene.
• Detailed examination of skeletal, muscular, and neural structures in mutant and wild-type mice.
• Analysis of vertebral column morphology, hindlimb bone structure, and innervation patterns.

Main Results:

• Hoxd-10 disruption resulted in hindlimb-specific gait and adduction defects.
• Mutant mice displayed homeotic transformations in sacral vertebrae (S2 and beyond).
• Hindlimb skeletal abnormalities included patellar position shift, sesamoid bone formation, and lower leg rotation.
• Neural defects involved reduced spinal segments in the sacral plexus and altered lumbar lateral motor column position.
• No significant hindlimb musculature alterations were observed.

Conclusions:

• The Hoxd-10 gene is critical for establishing regional identity within the spinal cord.
• Hoxd-10 influences the patterning of the spinal cord, suggesting intrinsic developmental components.
• Spinal cord patterning is not solely dictated by the surrounding mesoderm, with Hoxd-10 playing a key regulatory role.