STAG1

Description

The STAG1 (STAG1 cohesin complex component) is a protein-coding gene located on chromosome 3.

The STAG1 gene encodes SA-1, a subunit of the Cohesin complex. This complex is crucial for sister chromatid cohesion, homologous recombination, and DNA looping. In somatic cells, cohesin is made up of SMC3, SMC1, RAD21, and either SA1 or SA2, while in meiosis, it comprises SMC3, SMC1B, REC8, and SA3. SA1 is one of three human homologues of the yeast protein Scc3, the other two being SA2 and SA3. SA1 and SA2 are expressed in somatic cells, while SA3 is the primary SA paralogue in meiotic cells. SA2 is generally more abundant than SA1; however, in certain cell types, SA1 is the dominant form. SA1 binds stably to cohesin via the RAD21 subunit and acts as a platform for other regulatory subunits. The sequences of SA1 and SA2 share 75% conservation, with notable differences between their N-terminal and C-terminal regions. There is a non-profit organization dedicated to individuals with STAG1 gene mutations at www.stag1gene.org.

STAG1, also known as SA-1 or SCC3 homolog 1, is a key component of the cohesin complex. This complex is essential for holding sister chromatids together after DNA replication, ensuring that they are correctly separated during cell division. The cohesin complex forms a ring-like structure that encircles the sister chromatids. During anaphase, this ring is broken down, releasing the chromatids and allowing them to migrate to opposite poles of the cell. The cohesin complex may also have a role in the assembly of the spindle poles, which are the structures that guide chromosome separation during mitosis.

STAG1 is also known as MRD47, SA1, SCC3A.

Associated Diseases

• Mental retardation, autosomal dominant 47
• STAG1-related intellectual disability-facial dysmorphism-gastroesophageal reflux syndrome