HMG Transcription Factor Family
High mobility group (HMG or HMGB) proteins are a family of relatively low molecular weight
non-histone components in chromatin. HMG1 (also called HMG-T in fish) and HMG2 are two highly
related proteins that bind single-stranded DNA preferentially and unwind double-stranded DNA.
Although they have no sequence specificity, they have a high affinity for bent or distorted DNA,
and bend linear DNA. HMG1 and HMG2 contain two DNA-binding HMG-box domains (A and B) that show
structural and functional differences, and have a long acidic C-terminal domain rich in aspartic
and glutamic acid residues. The acidic tail modulates the affinity of the tandem HMG boxes in
HMG1 and 2 for a variety of DNA targets. HMG1 and 2 appear to play important architectural roles
in the assembly of nucleoprotein complexes in a variety of biological processes, for example
V(D)J recombination, the initiation of transcription, and DNA repair.
The profile in this entry describing the HMG-domains is much more general than the signature. In
addition to the HMG1 and HMG2 proteins, HMG-domains occur in single or multiple copies in the
following protein classes; the SOX family of transcription factors; SRY sex determining region Y
protein and related proteins; LEF1 lymphoid enhancer binding factor 1; SSRP recombination signal
recognition protein; MTF1 mitochondrial transcription factor 1; UBF1/2 nucleolar transcription
factors; Abf2 yeast ARS-binding factor; and Saccharomyces cerevisiae transcription factors Ixr1,
Rox1, Nhp6a, Nhp6b and Spp41.
33 predicted putative HMG TF peptide,
CDS, and cDNA sequences;
blast HSP, and multiple sequence alignment in
Soy - TFKB.
HMG box peptide sequences with
alignment and phylogeny tree.
45 HMG protein
and DNA
sequences with
annotations for soybean in PlantTFDB. Most are partial sequences.
Last updated by Dr. Jeff Chen on
June 5, 2009.
