SOX5

SOX5 is a transcription factor encoded by the SOX5 gene in humans. It belongs to the SOX (SRY-related HMG-box) family, specifically the SOX D subgroup that also includes SOX6. Members of this family share a conserved high-mobility group (HMG) DNA-binding domain and regulate gene expression. The SOX5 gene is subject to alternative splicing, yielding multiple isoforms with distinct or overlapping expression patterns.

During embryonic development, SOX5 is broadly expressed, with notable levels in the developing nervous system and skeletal tissues, including cartilage. In adults, expression is more restricted but persists in certain brain regions and cartilage.

In skeletal development, SOX5 functions together with SOX9 and SOX6 to promote chondrogenesis. Sox5 and Sox6 support cartilage matrix gene expression, and loss of Sox5 and Sox6 results in defective cartilage formation in model organisms, illustrating the cooperative regulation of chondrocyte differentiation.

In neural development, SOX5 contributes to the specification and maturation of certain neuron populations and to neural differentiation programs; it can act as a transcriptional regulator, functioning as an activator or repressor depending on context and partners.

Altered SOX5 expression or mutations have been linked to developmental disorders in humans, including skeletal and neurodevelopmental phenotypes in some studies; the precise spectrum and mechanisms are still being investigated.

SOX5 interacts with other SOX proteins, notably SOX9 and SOX6, and can recruit co-regulators to influence transcriptional outcomes. The gene is evolutionarily conserved across vertebrates, reflecting its roles in multiple developmental processes.