SOX1 is a gene that encodes a

transcription factor In molecular biology, a transcription factor (TF) (or sequence-specific DNA-binding factor) is a protein that controls the rate of transcription of genetic information from DNA to messenger RNA, by binding to a specific DNA sequence. The fu ...

with a

HMG-box In molecular biology, the HMG-box (high mobility group box) is a protein domain which is involved in DNA binding. Structure The structure of the HMG-box domain contains three alpha helices separated by loops (see figure to the right). Function ...

(

high mobility group High-Mobility Group or HMG is a group of chromosomal proteins that are involved in the regulation of DNA-dependent processes such as transcription, replication, recombination, and DNA repair. Families The HMG proteins are subdivided into 3 supe ...

)

DNA-binding domain A DNA-binding domain (DBD) is an independently folded protein domain that contains at least one structural motif that recognizes double- or single-stranded DNA. A DBD can recognize a specific DNA sequence (a recognition sequence) or have a gener ...

and functions primarily in

neurogenesis Neurogenesis is the process by which nervous system cells, the neurons, are produced by neural stem cells (NSCs). It occurs in all species of animals except the porifera (sponges) and placozoans. Types of NSCs include neuroepithelial cells (NECs) ...

. SOX1, SOX2 and SOX3, members of the

SOX gene family ''SOX'' genes ('' SRY''-related HMG-box genes) encode a family of transcription factors that bind to the minor groove in DNA, and belong to a super-family of genes characterized by a homologous sequence called the HMG-box (for high mobilit ...

(specifically the SOXB1 group), contain transcription factors related to '' SRY'', the testis-determining factor. SOX1 exerts its importance in its role in development of the

central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all par ...

(neurogenesis) and in particular the

development of the eye Eye formation in the human embryo begins at approximately three weeks into embryonic development and continues through the tenth week.Ort, D., David, H."Development of the Eye" Retrieved 22 April 2015. Cells from both the mesodermal and the ect ...

, where it is functionally redundant with SOX3 and to a lesser degree SOX2, and maintenance of neural progenitor cell identity. SOX1 expression is restricted to the

neuroectoderm Neuroectoderm (or neural ectoderm or neural tube epithelium) consists of cells derived from ectoderm. Formation of the neuroectoderm is first step in the development of the nervous system. The neuroectoderm receives bone morphogenetic protein-inhi ...

by proliferating progenitor cells in the

tetrapod Tetrapods (; ) are four-limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant and extinct amphibians, sauropsids ( reptiles, including dinosaurs and therefore birds) and synapsids (pelycosaurs, extinct theraps ...

embryo. The induction of this neuroectoderm occurs upon expression of the SOX1 gene. In

ectodermal The ectoderm is one of the three primary germ layers formed in early embryonic development. It is the outermost layer, and is superficial to the mesoderm (the middle layer) and endoderm (the innermost layer). It emerges and originates from t ...

cells committed to a certain cell fate, SOX1 has shown to be one of the earliest transcription factors expressed. In particular, SOX1 is first detected in the late head fold stage.

Clinical significance and research

Striatum development

SOX1 is expressed particularly in the

ventral striatum The striatum, or corpus striatum (also called the striate nucleus), is a nucleus (a cluster of neurons) in the subcortical basal ganglia of the forebrain. The striatum is a critical component of the motor and reward systems; receives glutam ...

, and Sox1-deficient mice have altered striatum development, leading e.g. to

epilepsy Epilepsy is a group of non-communicable neurological disorders characterized by recurrent epileptic seizures. Epileptic seizures can vary from brief and nearly undetectable periods to long periods of vigorous shaking due to abnormal electrical ...

Lens development

SOX1 has shown clinical significance in its direct regulation of gamma-crystallin genes, which is vital for lens development in mice. Gamma-crystallins serve as a key structural component in lens fiber cells in both mammals and amphibians. Research has shown direct deletion of the SOX1 gene in mice causes cataracts and microphthalmia. These mutant lenses fail to elongate due to the absence of gamma-crystallins.

SOXB1 group redundant roles

SOX1 is a member of the SOX gene family, in particular the SOXB1 group, which includes SOX1, SOX2, and SOX3. The SOX gene family encodes transcription factors. It is suggested the three members of the SOXB1 group have redundant roles in the development of neural stem cells. This group of SOX genes regulate neural progenitor identity. Each of these proteins have unique neural markers. Overexpression of either SOX1, SOX2, or SOX 3 increases neural progenitors and prevents neural differentiation. In non-mammalian vertebrates, loss of one SOXB1 protein results in minor phenotypic differences. This supports the claim that SOXB1 group proteins have redundant roles.

References

{{Use dmy dates, date=April 2017 Transcription factors Developmental genes and proteins

Clinical significance and research

Striatum development

Lens development

SOXB1 group redundant roles

See also

References