Geminin is required for Hox gene regulation to pattern the developing limb

Area of Science:

• Developmental Biology
• Molecular Biology
• Genetics

Background:

• Vertebrate limb development involves complex regulatory pathways.
• Precise 5' Hox transcription factor expression is critical for limb patterning and skeletal element formation.

Purpose of the Study:

• To identify novel regulators of vertebrate limb patterning.
• To investigate the role of Geminin (Gmnn) in limb development and Hox gene regulation.

Main Methods:

• Conditional Gmnn deficiency models in mice.
• Analysis of limb skeletal elements.
• Assessment of 5' Hox gene expression patterns.
• Investigation of Sonic Hedgehog (SHH) signaling pathway activity.

Main Results:

• Gmnn deficiency caused forelimb skeletal element reduction and altered 5' Hox gene expression proximally and anteriorly.
• A separate Gmnn deficiency model led to hindlimb skeletal defects, polydactyly, and an ectopic SHH signaling center.
• Reduced repressor form of GLI3 was observed in Gmnn-deficient hindlimbs, indicating SHH pathway dysregulation.

Conclusions:

• Geminin (Gmnn) is a novel regulator of vertebrate limb patterning.
• Gmnn modulates Hox gene expression critical for establishing limb skeletal identity.
• Gmnn influences SHH signaling pathways involved in hindlimb development.