SYR-related high mobility group (HMG) box (SOX) family proteins are a conserved group of transcriptional regulators defined by the presence of a highly conserved HMG box domain that mediates DNA binding []. This group represents the redundantly acting transcription factor SOX-12/11/4 proteins, which belong to the subgroup C of the SOX gene family. These proteins have almost identical DNA-binding domains that bind to the DNA sequence 5'-AACAAT-3' and have a highly conserved transactivation domain at their C-terminal []. They play an essential role in several developmental pathways including neurogenesis and skeletogenesis, affecting maintenance, proliferation and differentiation of progenitor cells in developing tissues such as the neural tube, branchial arches and somites [, , , ].SOX-11 is essential for neuronal development and it isalso required for body wall closure and spleen formation as well as proper development of the skeleton, the lung, and the heart. It enhances transcriptional activation through cooperatively binding with POU3F2/BRN2 or POU3F1/OCT6 to gene promoters [, ]. In humans, missense mutations that unable SOX11 to bind to DNA have been associated with a neurodevelopmental disorder whose features-microcephaly, global developmental delay, intellectual disability, and facial and digital abnormalities-are compatible with mild Coffin-Siris syndrome [].
