DNA-binding protein Ikaros also known as Ikaros family zinc finger protein 1 is a protein that in humans is encoded by the IKZF1 gene.[5][6][7]
Quick Facts Identifiers, Aliases ...
IKZF1 |
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Aliases | IKZF1, Hs.54452, IK1, IKAROS, LYF1, LyF-1, PPP1R92, PRO0758, ZNFN1A1, CVID13, IKAROS family zinc finger 1 |
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External IDs | OMIM: 603023; MGI: 1342540; HomoloGene: 55948; GeneCards: IKZF1; OMA:IKZF1 - orthologs |
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Ikaros is a transcription factor that is encoded by the IKZF genes of the Ikaros family zinc finger group. Zinc finger is a small structural motif of protein that allows protein binding to DNA or RNA molecule that is characterized by the coordination of one or more zinc ions (Zn2+) in order to stabilize the fold.
Ikaros displays crucial functions in the hematopoietic system and is a known regulator of immune cells development, mainly in early B cells, CD4+ T cells. Its dysfunction has been linked to the development of chronic lymphocytic leukemia.[8][9] In particular, Ikaros has been found in recent years to be a major tumor suppressor involved in human B-cell acute lymphoblastic leukemia[8] and that it also has a part in the differentiation and function of individual T helper cells.[10]
Ikaros also has a role during the later stages of B cell development during VDJ recombination in switch class of the antibody isotypes and expression of the B cell receptor.[11]
In Ikaros knockout mice, T cells but not B cells are generated late in mouse development due to late compensatory expression of the related gene Aiolos (IKZF3).[12] Ikaros point mutant mice are embryonic lethal due to anemia; they have severe defects in terminal erythrocyte and granulocyte differentiation, and excessive macrophage formation.[13] SNPs located near the 3' region of IKZF1 in humans have been linked to susceptibility to childhood acute lymphoblastic leukemia (ALL)[14] as well as type 1 diabetes.[15] The two effects appear to be in opposite directions, with the allele marking susceptibility to ALL protecting from T1D and vice versa.[15]
Further evidence shows that Ikaros regulates the development of medullary thymic epithelial cells (mTECs). Conditional deletion of Ikzf1 in thymic epithelial cells by Foxn1-Cre in mice, results in the dysregulation of various mTEC subsets, including the loss of Aire+ mTECs. The loss of Aire (Autoimmune regulator) expressing mTECs also causes global loss of tissue restricted antigens (TRAs) and Aire-dependent mimetic cell populations, with the loss of TRAs eventually leading to breakdown of immune tolerance.[16]
The Ikaros Zinc Finger (IkZF) family of transcription factors are known regulators of hematopoietic cell development and many immune cells including that of CD4+ T cells.
The IkZF family consists of five members: Ikaros (encoded by the gene Ikzf1), Helios (Ikzf2), Aiolos (Ikzf3), Eos (Ikzf4), and Pegasus (Ikzf5). These factors contain N-terminal zinc finger (ZF) domains, which are responsible for mediating direct interactions with DNA, and C-terminal ZFs, which facilitate homo- and heterodimerization between IkZF family members. [17]
IKZF1 is upregulated in granulocytes, B cells, CD4 and CD8 T cells, and NK cells, and downregulated in erythroblasts, megakaryocytes and monocytes.[18]
The mutation in the IKZF1 gene can cause dysfunction of the Ikaros transcription factor. The dysfunction affects expression in B cells that can lead to deregulation of the BCR signaling during B cell development and is associated with B cell transformation. The deregulation then can result in low proliferation rate and increased apoptosis of the B cells. The deregulation may be related with lymphoproliferative disorders and different forms of leukemia. [19]
IKZF1 has been shown to interact with:
Oliveira VC, Lacerda MP, Moraes BB, Gomes CP, Maricato JT, Souza OF, et al. (September 2019). "Deregulation of Ikaros expression in B-1 cells: New insights in the malignant transformation to chronic lymphocytic leukemia". Journal of Leukocyte Biology. 106 (3): 581–594. doi:10.1002/JLB.MA1118-454R. PMID 31299112. S2CID 196350761.
Sin JH, Sucharov J, Kashyap S, Wang Y, Proekt I, Liu X, et al. (October 2023). "Ikaros is a principal regulator of Aire+ mTEC homeostasis, thymic mimetic cell diversity, and central tolerance". Science Immunology. 8 (88): eabq3109. doi:10.1126/sciimmunol.abq3109. PMID 37889983. S2CID 264518068.
Oliveira VC, Lacerda MP, Moraes BB, Gomes CP, Maricato JT, Souza OF, et al. (July 2019). "Deregulation of Ikaros expression in B-1 cells: New insights in the malignant transformation to chronic lymphocytic leukemia". Journal of Leukocyte Biology. 106 (3): 581–594. doi:10.1002/JLB.MA1118-454R. PMID 31299112. S2CID 196350761.
- Tonnelle C, Calmels B, Maroc C, Gabert J, Chabannon C (January 2002). "Ikaros gene expression and leukemia". Leukemia & Lymphoma. 43 (1): 29–35. doi:10.1080/10428190210186. PMID 11908734. S2CID 23932398.
- Westman BJ, Mackay JP, Gell D (October 2002). "Ikaros: a key regulator of haematopoiesis". The International Journal of Biochemistry & Cell Biology. 34 (10): 1304–7. doi:10.1016/S1357-2725(02)00070-5. PMID 12127581.
- Molnár A, Wu P, Largespada DA, Vortkamp A, Scherer S, Copeland NG, et al. (January 1996). "The Ikaros gene encodes a family of lymphocyte-restricted zinc finger DNA binding proteins, highly conserved in human and mouse". Journal of Immunology. 156 (2): 585–92. doi:10.4049/jimmunol.156.2.585. PMID 8543809. S2CID 24893140.
- Nietfeld W, Meyerhans A (January 1996). "Cloning and sequencing of hIk-1, a cDNA encoding a human homologue of mouse Ikaros/LyF-1". Immunology Letters. 49 (1–2): 139–41. doi:10.1016/0165-2478(95)02479-4. PMID 8964602.
- Morgan B, Sun L, Avitahl N, Andrikopoulos K, Ikeda T, Gonzales E, et al. (April 1997). "Aiolos, a lymphoid restricted transcription factor that interacts with Ikaros to regulate lymphocyte differentiation". The EMBO Journal. 16 (8): 2004–13. doi:10.1093/emboj/16.8.2004. PMC 1169803. PMID 9155026.
- Kelley CM, Ikeda T, Koipally J, Avitahl N, Wu L, Georgopoulos K, et al. (April 1998). "Helios, a novel dimerization partner of Ikaros expressed in the earliest hematopoietic progenitors". Current Biology. 8 (9): 508–15. Bibcode:1998CBio....8..508K. doi:10.1016/S0960-9822(98)70202-7. PMID 9560339. S2CID 17835058.
- Sun L, Heerema N, Crotty L, Wu X, Navara C, Vassilev A, et al. (January 1999). "Expression of dominant-negative and mutant isoforms of the antileukemic transcription factor Ikaros in infant acute lymphoblastic leukemia". Proceedings of the National Academy of Sciences of the United States of America. 96 (2): 680–5. Bibcode:1999PNAS...96..680S. doi:10.1073/pnas.96.2.680. PMC 15196. PMID 9892693.
- Kim J, Sif S, Jones B, Jackson A, Koipally J, Heller E, et al. (March 1999). "Ikaros DNA-binding proteins direct formation of chromatin remodeling complexes in lymphocytes". Immunity. 10 (3): 345–55. doi:10.1016/S1074-7613(00)80034-5. PMID 10204490.
- Honma Y, Kiyosawa H, Mori T, Oguri A, Nikaido T, Kanazawa K, et al. (March 1999). "Eos: a novel member of the Ikaros gene family expressed predominantly in the developing nervous system". FEBS Letters. 447 (1): 76–80. doi:10.1016/S0014-5793(99)00265-3. PMID 10218586. S2CID 28898354.
- Koipally J, Renold A, Kim J, Georgopoulos K (June 1999). "Repression by Ikaros and Aiolos is mediated through histone deacetylase complexes". The EMBO Journal. 18 (11): 3090–100. doi:10.1093/emboj/18.11.3090. PMC 1171390. PMID 10357820.
- Sun L, Goodman PA, Wood CM, Crotty ML, Sensel M, Sather H, et al. (December 1999). "Expression of aberrantly spliced oncogenic ikaros isoforms in childhood acute lymphoblastic leukemia". Journal of Clinical Oncology. 17 (12): 3753–66. doi:10.1200/JCO.1999.17.12.3753. PMID 10577847.
- Hosokawa Y, Maeda Y, Ichinohasama R, Miura I, Taniwaki M, Seto M (April 2000). "The Ikaros gene, a central regulator of lymphoid differentiation, fuses to the BCL6 gene as a result of t(3;7)(q27;p12) translocation in a patient with diffuse large B-cell lymphoma". Blood. 95 (8): 2719–21. doi:10.1182/blood.V95.8.2719. PMID 10753856.
- Koipally J, Georgopoulos K (June 2000). "Ikaros interactions with CtBP reveal a repression mechanism that is independent of histone deacetylase activity". The Journal of Biological Chemistry. 275 (26): 19594–602. doi:10.1074/jbc.M000254200. PMID 10766745.
- Perdomo J, Holmes M, Chong B, Crossley M (December 2000). "Eos and pegasus, two members of the Ikaros family of proteins with distinct DNA binding activities". The Journal of Biological Chemistry. 275 (49): 38347–54. doi:10.1074/jbc.M005457200. PMID 10978333.
- Payne KJ, Nicolas JH, Zhu JY, Barsky LW, Crooks GM (August 2001). "Cutting edge: predominant expression of a novel Ikaros isoform in normal human hemopoiesis". Journal of Immunology. 167 (4): 1867–70. doi:10.4049/jimmunol.167.4.1867. PMID 11489963.
- Koipally J, Heller EJ, Seavitt JR, Georgopoulos K (April 2002). "Unconventional potentiation of gene expression by Ikaros". The Journal of Biological Chemistry. 277 (15): 13007–15. doi:10.1074/jbc.M111371200. PMID 11799125.
- Dorsam G, Goetzl EJ (April 2002). "Vasoactive intestinal peptide receptor-1 (VPAC-1) is a novel gene target of the hemolymphopoietic transcription factor Ikaros". The Journal of Biological Chemistry. 277 (16): 13488–93. doi:10.1074/jbc.M107922200. PMID 11812772.