| Written | 2007-04 | Rupa Sridharan, Stephen Smale |
| Room 6730 MacDonald Research Laboratories, Howard Hughes Medical Institute, 675 Charles Young Drive South, University of California, Los Angeles, CA 90095-1662, USA. |
| Identity |
| Alias_names | ZNFN1A2 |
| zinc finger protein, subfamily 1A, 2 (Helios) | |
| IKAROS family zinc finger 2 (Helios) | |
| Alias_symbol (synonym) | Helios |
| Other alias | Mouse Ikzf2 |
| HGNC (Hugo) | IKZF2 |
| LocusID (NCBI) | 22807 |
| Atlas_Id | 42885 |
| Location | 2q34 [Link to chromosome band 2q34] |
| Location_base_pair | Starts at 212999686 and ends at 213150334 bp from pter ( according to hg19-Feb_2009) [Mapping IKZF2.png] |
| Fusion genes (updated 2017) | Data from Atlas, Mitelman, Cosmic Fusion, Fusion Cancer, TCGA fusion databases with official HUGO symbols (see references in chromosomal bands) |
| ERBB4 (2q34) / IKZF2 (2q34) | IKZF2 (2q34) / BCL11B (14q32.2) | IKZF2 (2q34) / DOCK2 (5q35.1) | |
| IKZF2 (2q34) / MICU2 (13q12.11) | IKZF2 (2q34) / SPAG16 (2q34) |
| Note | Belongs to the Ikaros family of zinc finger containing DNA binding proteins. |
| DNA/RNA |
| Description | 143kb encoding 7 exons. |
| Transcription | 12kb transcript, alternatively spliced to give two predominant isoforms. |
| Protein |
| Note | 526 amino acids. Mouse protein migrates at 70kD. |
 | |
| Helios with the zinc finger domain shown as blocks and the exon junctions in black lines. | |
| 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. |
| Implicated in |
| Note | |
| Entity | Leukemia |
| Note | Shorter isoforms of Helios are expressed in certain human leukemias. They may function as dominant negative inhibitors of full-length proteins due to the lack of DNA binding domain. However, dominant negative functions have not been demonstrated experimentally. |
| Disease | T cell acute lymphoblastic leukemia. |
| Entity | Lymphoma |
| Note | Overexpression of Helios in B cells of mice promotes lymphomagenesis. Overexpression of a DNA binding mutant in hematopoietic progenitors leads to aggressive and transplantable T cell lymphomas in 60% of the mice. |
| Bibliography |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| Citation |
| This paper should be referenced as such : |
| Sridharan, Rupa ; Smale, Stephen |
| IKZF2 (IKAROS family zinc finger 2) |
| Atlas Genet Cytogenet Oncol Haematol. 2007;11(4):270-271. |
| Free journal version : [ pdf ] [ DOI ] |
| On line version : http://AtlasGeneticsOncology.org/Genes/IKZF2ID42885ch2q34.html |
| Other Leukemias implicated (Data extracted from papers in the Atlas) [ 1 ] |
|
t(2;14)(q34;q32) IKZF2/BCL11B
|
| Other Solid tumors implicated (Data extracted from papers in the Atlas) [ 1 ] |
|
t(2;13)(q34;q12) IKZF2/MICU2
|
| External links |
| REVIEW articles | automatic search in PubMed |
| Last year publications | automatic search in PubMed |
| © Atlas of Genetics and Cytogenetics in Oncology and Haematology | indexed on : Mon Jul 16 09:50:44 CEST 2018 |
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