HMBOX1

Homeobox containing 1, also known as homeobox telomere-binding protein 1 (HOT1), is a protein that in humans is encoded by the HMBOX1 gene.^[5] HMBOX1 directly binds to the double-stranded repeat sequence of telomeres.^[6][7]

PDBOrtholog search: PDBe RCSB

AliasesHMBOX1, HNF1LA, HOT1, PBHNF, homeobox containing 1, TAH1

External IDsMGI: 2445066; HomoloGene: 11589; GeneCards: HMBOX1; OMA:HMBOX1 - orthologs

Chr.Chromosome 8 (human)^[1]

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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)[1] Band 8p21.1-p12 Start 28,890,395 bp[1] End 29,064,764 bp[1]
Gene location (Mouse) Chr. Chromosome 14 (mouse)[2] Band 14|14 D1 Start 65,049,049 bp[2] End 65,187,320 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) 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 BioGPS 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 Species Human Mouse Entrez 79618 219150 Ensembl ENSG00000147421 ENSMUSG00000021972 UniProt Q6NT76 Q8BJA3 RefSeq (mRNA) 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 RefSeq (protein) 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 Location (UCSC) Chr 8: 28.89 – 29.06 Mb Chr 14: 65.05 – 65.19 Mb PubMed search [3] [4]
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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).^[6] Subsequently, direct binding to telomeric DNA was demonstrated through a co-crystal structure of the DNA-binding domain of HMBOX1 with telomeric DNA.^[7] Loss-of-function and gain-of-function experiments classify HMBOX1 as a positive regulator of telomere length.^[7][8] HMBOX1 had originally been described as a transcriptional repressor based on reporter gene assays,^[9] but genome-wide approaches using RNA-seq and ChIP-seq see little to no such effect at least in several cancer cell lines.^[10]