HMBOX1

HMBOX1
Available structures
PDB	Ortholog search: PDBe RCSB
List of PDB id codes
	2CUF, 4J19
Identifiers
Aliases	HMBOX1, HNF1LA, HOT1, PBHNF, homeobox containing 1, TAH1
External IDs	MGI: 2445066; HomoloGene: 11589; GeneCards: HMBOX1; OMA:HMBOX1 - orthologs
Gene location (Human)
Chr.	Chromosome 8 (human)
End	29,064,764 bp
Gene location (Mouse)
Chr.	Chromosome 14 (mouse)
End	65,187,320 bp
RNA expression pattern
	Top expressed in
	epithelium of colon; ; spinal ganglia; ; right adrenal cortex; ; olfactory bulb; ; secondary oocyte; ; cardia; ; left adrenal cortex; ; pars reticulata; ; ventral tegmental area; ; trigeminal ganglion;
	Top expressed in
	genital tubercle; ; neural layer of retina; ; superior frontal gyrus; ; ventricular zone; ; tail of embryo; ; Rostral migratory stream; ; dentate gyrus of hippocampal formation granule cell; ; gastrula; ; cerebellar cortex; ; lumbar spinal ganglion;
	More reference expression data
	n/a
Gene ontology
Molecular function	DNA binding; telomerase activity; double-stranded telomeric DNA binding; protein binding; identical protein binding; telomeric DNA binding; DNA-binding transcription repressor activity, RNA polymerase II-specific; sequence-specific DNA binding; protein-containing complex binding; DNA-binding transcription factor activity, RNA polymerase II-specific;
Cellular component	cytoplasm; nucleus; telomerase holoenzyme complex; nucleoplasm; cytosol; nuclear body; telomere; chromosome; Cajal body; PML body;
Biological process	positive regulation of transcription, DNA-templated; positive regulation of telomere maintenance via telomerase; negative regulation of transcription, DNA-templated; regulation of transcription, DNA-templated; positive regulation of telomerase activity; transcription, DNA-templated; RNA-dependent DNA biosynthetic process; positive regulation of chromatin binding; negative regulation of transcription by RNA polymerase II; regulation of telomerase activity;
	Sources:Amigo / QuickGO
Orthologs
	79618
	219150
	ENSG00000147421
	ENSMUSG00000021972
	Q6NT76
	Q8BJA3
NM_001135726; NM_024567; NM_001324382; NM_001324383; NM_001324384;
	NM_001324385; NM_001324386; NM_001324387; NM_001324388; NM_001324389; NM_001324390; NM_001324391; NM_001324392; NM_001324393; NM_001324394; NM_001324395; NM_001330498
	NM_177338; NM_001347626; NM_001347627
NP_001129198; NP_001311311; NP_001311312; NP_001311313; NP_001311314;
	NP_001311315; NP_001311316; NP_001311317; NP_001311318; NP_001311319; NP_001311320; NP_001311321; NP_001311322; NP_001311323; NP_001311324; NP_001317427; NP_078843
	NP_001334555; NP_001334556; NP_796312
	Wikidata
View/Edit Human	View/Edit Mouse

Homeobox containing 1, also known as homeobox telomere-binding protein 1 (HOT1), is a protein that in humans is encoded by the HMBOX1 gene. HMBOX1 directly binds to the double-stranded repeat sequence of telomeres.

HMBOX1 has originally been identified to associate with telomeric chromatin in telomerase-positive cancer cells and cancer cells that maintain their telomeres based on the Alternative Lengthening of Telomeres (ALT) mechanism by the 'reverse ChIP' technique PICh (Proteomics of Isolated Chromatin segments). Subsequently, direct binding to telomeric DNA was demonstrated through a co-crystal structure of the DNA-binding domain of HMBOX1 with telomeric DNA. Loss-of-function and gain-of-function experiments classify HMBOX1 as a positive regulator of telomere length. HMBOX1 had originally been described as a transcriptional repressor based on reporter gene assays, but genome-wide approaches using RNA-seq and ChIP-seq see little to no such effect at least in several cancer cell lines.