| Note | 526 amino acids. Mouse protein migrates at 70kD. |
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| | Helios with the zinc finger domain shown as blocks and the exon junctions in black lines. |
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| Description | Largest isoform contains four N-terminal zinc fingers used for DNA binding and two C terminal zinc fingers for homodimerization and heterodimerization with other Ikaros family members. |
| Expression | Largely restricted to the thymus. In mice, besides thymocytes and T cells, low levels are found in proB cells and bone marrow multipotent progenitors. |
| Localisation | Nuclear. Often localizes to the pericentric heterochromatin as punctate spots in cycling cells, with diffuse nuclear localization in non-cycling cells. |
| Function | Helios is thought to be important for T cell development and may function as a repressor of transcription. However, Helios mutant mice have not been reported. In mice, Helios can recruit the NuRD chromatin remodeling complex to the pericentric heterochromatin. |
| Homology | High level of identity to Ikaros over the zinc finger domains. |
| Transgenic expression of Helios in B lineage cells alters B cell properties and promotes lymphomagenesis. |
| Dovat S, Montecino-Rodriguez E, Schuman V, Teitell MA, Dorshkind K, Smale ST |
| Journal of immunology (Baltimore, Md. : 1950). 2005 ; 175 (6) : 3508-3515. |
| PMID 16148093 |
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| Helios, a T cell-restricted Ikaros family member that quantitatively associates with Ikaros at centromeric heterochromatin. |
| Hahm K, Cobb BS, McCarty AS, Brown KE, Klug CA, Lee R, Akashi K, Weissman IL, Fisher AG, Smale ST |
| Genes & development. 1998 ; 12 (6) : 782-796. |
| PMID 9512513 |
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| Human Helios, an Ikaros-related zinc finger DNA binding protein: cDNA cloning and tissue expression pattern. |
| Hosokawa Y, Maeda Y, Seto M |
| Immunogenetics. 1999 ; 50 (1-2) : 106-108. |
| PMID 10541817 |
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| Helios, a novel dimerization partner of Ikaros expressed in the earliest hematopoietic progenitors. |
| Kelley CM, Ikeda T, Koipally J, Avitahl N, Wu L, Georgopoulos K, Morgan BA |
| Current biology : CB. 1998 ; 8 (9) : 508-515. |
| PMID 9560339 |
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| Overexpression of novel short isoforms of Helios in a patient with T-cell acute lymphoblastic leukemia. |
| Nakase K, Ishimaru F, Fujii K, Tabayashi T, Kozuka T, Sezaki N, Matsuo Y, Harada M |
| Experimental hematology. 2002 ; 30 (4) : 313-317. |
| PMID 11937265 |
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| Expression of a non-DNA-binding isoform of Helios induces T-cell lymphoma in mice. |
| Zhang Z, Swindle CS, Bates JT, Ko R, Cotta CV, Klug CA |
| Blood. 2007 ; 109 (5) : 2190-2197. |
| PMID 17110463 |
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