HMGB3

This gene encodes a member of a family of proteins containing one or more high mobility group DNA-binding motifs. The encoded protein plays an important role in maintaining stem cell populations, and may be aberrantly expressed in tumor cells. A mutation in this gene was associated with microphthalmia, syndromic 13. There are numerous pseudogenes of this gene on multiple chromosomes. Alternative splicing results in multiple transcript variants.

Full Name

High Mobility Group Box 3

Function

Multifunctional protein with various roles in different cellular compartments. May act in a redox sensitive manner. Associates with chromatin and binds DNA with a preference to non-canonical DNA structures such as single-stranded DNA. Can bent DNA and enhance DNA flexibility by looping thus providing a mechanism to promote activities on various gene promoters (By similarity).

Proposed to be involved in the innate immune response to nucleic acids by acting as a cytoplasmic promiscuous immunogenic DNA/RNA sensor (By similarity).

Negatively regulates B-cell and myeloid cell differentiation. In hematopoietic stem cells may regulate the balance between self-renewal and differentiation. Involved in negative regulation of canonical Wnt signaling (By similarity).

Biological Process

DNA geometric change Source: AgBase
DNA recombination Source: UniProtKB
Innate immune response Source: UniProtKB-KW
Negative regulation of B cell differentiation Source: Ensembl
Negative regulation of myeloid cell differentiation Source: Ensembl
Regulation of transcription by RNA polymerase II Source: GO_Central

Cellular Location

Nucleus; Cytoplasm; Chromosome

Involvement in disease

Microphthalmia, syndromic, 13 (MCOPS13):
A form of microphthalmia, a disorder of eye formation, ranging from small size of a single eye to complete bilateral absence of ocular tissues (anophthalmia). In many cases, microphthalmia/anophthalmia occurs in association with syndromes that include non-ocular abnormalities. MCOPS13 patients exhibit colobomatous microphthalmia with microcephaly, short stature, and psychomotor retardation.

PTM

Reduction/oxidation of cysteine residues Cys-23, Cys-45 and Cys-104 and a possible intramolecular disulfide bond involving Cys-23 and Cys-45 give rise to different redox forms with specific functional activities in various cellular compartments: 1- fully reduced HMGB3 (HMGB3C23hC45hC104h), 2- disulfide HMGB3 (HMGB3C23-C45C104h) and 3- sulfonyl HMGB3 (HMGB3C23soC45soC104so).