HMBOX1

{{Short description|Protein-coding gene in the species Homo sapiens}} {{Infobox_gene}}

'''Homeobox containing 1''', also known as '''homeobox telomere-binding protein 1''' ('''HOT1'''), is a protein that in humans is encoded by the '''HMBOX1''' gene.<ref name="entrez">{{cite web| title = Entrez Gene: Homeobox containing 1 | url = https://www.ncbi.nlm.nih.gov/gene?db=gene&cmd=retrieve&list_uids=79618 }}</ref> HMBOX1 directly binds to the double-stranded repeat sequence of telomeres.<ref name="Déjardin_2009">{{cite journal | vauthors = Déjardin J, Kingston RE | title = Purification of proteins associated with specific genomic Loci | journal = Cell | volume = 136 | issue = 1 | pages = 175–86 | date = January 2009 | pmid = 19135898 | pmc = 3395431 | doi = 10.1016/j.cell.2008.11.045 }}</ref><ref name="Kappei_2013">{{cite journal | vauthors = Kappei D, Butter F, Benda C, Scheibe M, Draškovič I, Stevense M, Novo CL, Basquin C, Araki M, Araki K, Krastev DB, Kittler R, Jessberger R, Londoño-Vallejo JA, Mann M, Buchholz F | title = HOT1 is a mammalian direct telomere repeat-binding protein contributing to telomerase recruitment | journal = The EMBO Journal | volume = 32 | issue = 12 | pages = 1681–701 | date = June 2013 | pmid = 23685356 | pmc = 3680732 | doi = 10.1038/emboj.2013.105 }}</ref>

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).<ref name="Déjardin_2009" /> Subsequently, direct binding to telomeric DNA was demonstrated through a co-crystal structure of the DNA-binding domain of HMBOX1 with telomeric DNA.<ref name="Kappei_2013" /> Loss-of-function and gain-of-function experiments classify HMBOX1 as a positive regulator of telomere length.<ref name="Kappei_2013" /><ref>{{cite journal | vauthors = Zhou S, Xiao Y, Zhuang Y, Liu Y, Zhao H, Yang H, Xie C, Zhou F, Zhou Y | title = Knockdown of homeobox containing 1 increases the radiosensitivity of cervical cancer cells through telomere shortening | journal = Oncology Reports | volume = 38 | issue = 1 | pages = 515–521 | date = July 2017 | pmid = 28628186 | doi = 10.3892/or.2017.5707 | doi-access = free }}</ref> HMBOX1 had originally been described as a transcriptional repressor based on reporter gene assays,<ref>{{cite journal | vauthors = Chen S, Saiyin H, Zeng X, Xi J, Liu X, Li X, Yu L | title = Isolation and functional analysis of human HMBOX1, a homeobox containing protein with transcriptional repressor activity | journal = Cytogenetic and Genome Research | volume = 114 | issue = 2 | pages = 131–6 | date = 2006 | pmid = 16825764 | doi = 10.1159/000093328 | s2cid = 21067536 }}</ref> but genome-wide approaches using RNA-seq and ChIP-seq see little to no such effect at least in several cancer cell lines.<ref>{{cite journal | vauthors = Jahn A, Rane G, Paszkowski-Rogacz M, Sayols S, Bluhm A, Han CT, Draškovič I, Londoño-Vallejo JA, Kumar AP, Buchholz F, Butter F, Kappei D | title = ZBTB48 is both a vertebrate telomere-binding protein and a transcriptional activator | journal = EMBO Reports | volume = 18 | issue = 6 | pages = 929–946 | date = June 2017 | pmid = 28500257 | pmc = 5452029 | doi = 10.15252/embr.201744095 }}</ref>

== References ==

== Further reading ==

Category:Genes on human chromosome 8 Category:Telomeres