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HGNC Approved Gene Symbol: TRIM24
Cytogenetic location: 7q33-q34 Genomic coordinates (GRCh38) : 7:138,460,259-138,589,996 (from NCBI)
Hormonal regulation of gene activity is mediated by nuclear receptors acting as ligand-activated transcription factors. The activity of the ligand-dependent activation function, or AF2, of the receptors requires intermediary factors that interact with the AF2-activating domain, a C-terminal region that is highly conserved in the nuclear receptor family. Thenot et al. (1997) isolated human breast cancer cell cDNAs that encode transcription intermediary factor-1 (TIF1), a protein that is able to bind to the AF2-activating domain of the estrogen receptor (ESR; e.g., 133430). The deduced 1,013-amino acid TIF1 protein, which is more than 92% conserved with mouse Tif1, contains several domains: a RING finger, B-box fingers, a coiled-coil domain, a PHD homeodomain finger, and a bromodomain. A 26-amino acid region of TIF1 is sufficient for its hormone-dependent binding to the ESR. Thenot et al. (1997) demonstrated that the AF2-activating domain of ESR is required but not sufficient for the binding of TIF1, that TIF1 association with DNA-bound ESR requires the presence of estradiol, and that TIF1 interacts selectively with different nuclear receptors. The authors identified a cDNA variant that encodes a TIF1 isoform containing a 34-amino acid insertion. Northern blot analysis detected a major 4.5-kb transcript in MCF7 breast cancer cells.
In the TIF1 proteins, Venturini et al. (1999) identified a 25-amino acid stretch rich in tryptophan and phenylalanine located downstream of the coiled-coil motif. This 25-amino acid stretch is highly conserved between TIF1A, TIF1B (601742), and TIF1G (605769), and the authors termed this the TIF1 signature sequence, or TSS. Luciferase analysis determined that TIF1A, like TIF1G and TIF1B, represses transcription by binding through the TSS to promoter regions.
Fusion of PML (102578) and TIF1A to RARA (180240) and BRAF (164757), respectively, results in the production of PML-RAR-alpha and TIF1-alpha-B-RAF (T18) oncoproteins. Zhong et al. (1999) showed that PML, TIF1-alpha, and RXR-alpha (180245)/RAR-alpha function together in a retinoic acid-dependent transcription complex. Zhong et al. (1999) found that PML acts as a ligand-dependent coactivator of RXR-alpha/RARA-alpha. PML interacts with TIF1-alpha and CREB-binding protein (CBP; 600140). In PML -/- cells, the retinoic acid-dependent induction of genes such as RARB2 and the ability of TIF1-alpha and CBP to act as transcriptional coactivators on retinoic acid are impaired. Zhong et al. (1999) showed that both PML and TIF1-alpha are growth suppressors required for the growth-inhibitory activity of retinoic acid. T18, similar to PML-RAR-alpha, disrupts the retinoic acid-dependent activity of this complex in a dominant-negative manner, resulting in a growth advantage. PML-RAR-alpha was the first example of an oncoprotein generated by the fusion of 2 molecules participating in the same pathway, specifically the fusion of a transcription factor to one of its own cofactors. Since the PML and RAR-alpha pathways converge at the transcriptional level, there is no need for a double-dominant-negative product to explain the pathogenesis of acute promyelocytic leukemia, or APL.
Using chromatin immunoprecipitation (ChIP), Tsai et al. (2010) demonstrated that TRIM24 binds chromatin and estrogen receptor (see 133430) to activate estrogen-dependent genes associated with cellular proliferation and tumor development. Aberrant expression of TRIM24 negatively correlated with survival of breast cancer (see 114480) patients. Based on these findings and analysis of 3-dimensional TRIM24 structures, Tsai et al. (2010) concluded that the PHD-Bromo of TRIM24 provides a structural rationale for chromatin activation through a noncanonic histone signature, establishing a new route by which chromatin readers may influence cancer pathogenesis.
Theurillat et al. (2014) analyzed changes in the ubiquitin landscape induced by prostate cancer-associated mutations of SPOP (602650), an E3 ubiquitin ligase substrate-binding protein. SPOP mutants impaired ubiquitylation of a subset of proteins in a dominant-negative fashion. Of these, DEK (125264) and TRIM24 emerged as effector substrates consistently upregulated by SPOP mutants.
Crystal Structure
Tsai et al. (2010) reported that TRIM24 functions in humans as a reader of dual histone marks by means of tandem PHD and Bromo regions. The 3-dimensional structure of the PHD-Bromo region of TRIM24 revealed a single functional unit for combinatorial recognition of histone-3 (see 602810) unmodified at lysine-4 (H3K4) and acetylated H3K23 within the same histone tail.
By FISH, Venturini et al. (1999) mapped the TIF1 gene to 7q32-q34.
The predominant molecular lesions in papillary thyroid carcinomas (PTC; see 188550), which were particularly prevalent after the Chernobyl nuclear reactor accident, are rearrangements of the RET receptor tyrosine kinase (164761). Klugbauer and Rabes (1999) identified 2 novel types of RET rearrangements, which they termed PTC6 and PTC7. In PTC6, RET is fused to the N-terminal part of TIF1A, and in PTC7, RET is fused to a C-terminal part of TIF1G.
Le Douarin et al. (1995) isolated mouse cDNAs encoding 2 Tif1 isoforms, 1 of which contains a 34-amino acid insertion relative to the other. Northern blot analysis detected Tif1 expression in all mouse tissues tested. The authors showed that Tif1 can enhance the activity of the ligand-dependent AF2 of the nuclear receptors RXR (e.g., 180247) and RAR (e.g., 180240) in yeast. They found that the N-terminal portion of the mouse T18 oncogene corresponds to the N-terminal portion of mouse Tif1.
Beckstead et al. (2001) found that the Drosophila 'bonus' (bon) gene encodes a homolog of the vertebrate TIF1 transcriptional cofactors. Bon is required for male viability, molting, and numerous events in metamorphosis, including leg elongation, bristle development, and pigmentation. Most of these processes are associated with genes that are implicated in the ecdysone pathway, a nuclear hormone receptor pathway required throughout Drosophila development. Bon is associated with sites on the polytene chromosomes and can interact with numerous Drosophila nuclear receptor proteins. In vivo, bon behaves as a transcriptional inhibitor.
Hepatocellular carcinoma (HCC; 114550) is a major cause of death worldwide. Khetchoumian et al. (2007) provided evidence that the ligand-dependent nuclear receptor coregulator Trim24 functions in mice as a liver-specific tumor suppressor. In Trim24-null mice, hepatocytes failed to execute proper cell cycle withdrawal during the neonatal-to-adult transition and continued to cycle in adult livers, becoming prone to a continuum of cellular alterations that progress toward metastatic HCC. Using pharmacologic approaches, Khetchoumian et al. (2007) showed that inhibition of retinoic acid signaling markedly reduces hepatocyte proliferation in Trim24 -/- mice. They further showed that deletion of a single retinoic acid receptor-alpha (Rara; 180240) allele in a Trim24-null background suppresses HCC development and restores wildtype expression of retinoic acid-responsive genes in the liver, thus demonstrating that in this genetic background Rara expresses an oncogenic activity correlating with a dysregulation of the retinoic acid signaling pathway. The results not only provided genetic evidence that Trim24 and Rara coregulate hepatocarcinogenesis in an antagonistic manner but also suggested that aberrant activation of Rara is deleterious to liver homeostasis.
Ignat et al. (2008) found that, in addition to occasional metastases from liver tumors, Tif1a-null mice developed calcification in connective tissues that increased with age. Calcium deposits developed in kidneys of Tif1a-null mice at 3 months of age and were initially restricted to glomerular arterioles and medium-sized arteries. At later ages, calcification increased in kidney and was also observed in tongue, brown fat, snout dermis, heart, retina, thyroid, lung, and vibrissae. The sites of ectopic calcification resembled those seen in mice with activating mutations in the calcium sensor receptor gene (CASR; 601199), and expression of Casr and several other vitamin D receptor (VDR; 601769) target genes was increased in Tif1a-null kidney. The calcifying arteriopathy of Tif1a-null mice shared features with human age-related Monckeberg disease, and the results supported the hypothesis that aging is promoted by increased activity of the vitamin D signaling pathway.
Beckstead, R., Ortiz, J. A., Sanchez, C., Prokopenko, S. N., Chambon, P., Losson, R., Bellen, H. J. Bonus, a Drosophila homolog of TIF1 proteins, interacts with nuclear receptors and can inhibit beta-FTZ-F1-dependent transcription. Molec. Cell 7: 753-765, 2001. [PubMed: 11336699] [Full Text: https://doi.org/10.1016/s1097-2765(01)00220-9]
Ignat, M., Teletin, M., Tisserand, J., Khetchoumian, K., Dennefeld, C., Chambon, P., Losson, R., Mark, M. Arterial calcifications and increased expression of vitamin D receptor targets in mice lacking TIF1-alpha. Proc. Nat. Acad. Sci. 105: 2598-2603, 2008. [PubMed: 18287084] [Full Text: https://doi.org/10.1073/pnas.0712030105]
Khetchoumian, K., Teletin, M., Tisserand, J., Mark, M., Herquel, B., Ignat, M., Zucman-Rossi, J., Cammas, F., Lerouge, T., Thibault, C., Metzger, D., Chambon, P., Losson, R. Loss of Trim24 (Tif1-alpha) gene function confers oncogenic activity to retinoic acid receptor alpha. Nature Genet. 39: 1500-1506, 2007. [PubMed: 18026104] [Full Text: https://doi.org/10.1038/ng.2007.15]
Klugbauer, S., Rabes, H. M. The transcription coactivator HTIF1 and a related protein are fused to the RET receptor tyrosine kinase in childhood papillary thyroid carcinomas. Oncogene 18: 4388-4393, 1999. [PubMed: 10439047] [Full Text: https://doi.org/10.1038/sj.onc.1202824]
Le Douarin, B., Zechel, C., Garnier, J.-M., Lutz, Y., Tora, L., Pierrat, B., Heery, D., Gronemeyer, H., Chambon, P., Losson, R. The N-terminal part of TIF1, a putative mediator of the ligand-dependent activation function (AF-2) of nuclear receptors, is fused to B-raf in the oncogenic protein T18. EMBO J. 14: 2020-2033, 1995. [PubMed: 7744009] [Full Text: https://doi.org/10.1002/j.1460-2075.1995.tb07194.x]
Thenot, S., Henriquet, C., Rochefort, H., Cavailles, V. Differential interaction of nuclear receptors with the putative human transcriptional coactivator hTIF1. J. Biol. Chem. 272: 12062-12068, 1997. [PubMed: 9115274] [Full Text: https://doi.org/10.1074/jbc.272.18.12062]
Theurillat, J.-P. P., Udeshi, N. D., Errington, W. J., Svinkina, T., Baca, S. C., Pop, M., Wild, P. J., Blattner, M., Groner, A. C., Rubin, M. A., Moch, H., Prive, G. G., Carr, S. A., Garraway, L. A. Ubiquitylome analysis identifies dysregulation of effector substrates in SPOP-mutant prostate cancer. Science 346: 85-89, 2014. [PubMed: 25278611] [Full Text: https://doi.org/10.1126/science.1250255]
Tsai, W.-W., Wang, Z., Yiu, T. T., Akdemir, K. C., Xia, W., Winter, S., Tsai, C.-Y., Shi, X., Schwarzer, D., Plunkett, W., Aronow, B., Gozani, O., Fischle, W., Hung, M.-C., Patel, D. J., Barton, M. C. TRIM24 links a non-canonical histone signature to breast cancer. Nature 468: 927-932, 2010. [PubMed: 21164480] [Full Text: https://doi.org/10.1038/nature09542]
Venturini, L., You, J., Stadler, M., Galien, R., Lallemand, V., Koken, M. H. M., Mattei, M. G., Ganser, A., Chambon, P., Losson, R., de The, H. TIF1-gamma, a novel member of the transcriptional intermediary factor 1 family. Oncogene 18: 1209-1217, 1999. [PubMed: 10022127] [Full Text: https://doi.org/10.1038/sj.onc.1202655]
Zhong, S., Delva, L., Rachez, C., Cenciarelli, C., Gandini, D., Zhang, H., Kalantry, S., Freedman, L. P., Pandolfi, P. P. A RA-dependent, tumour-growth suppressive transcription complex is the target of the PML-RAR-alpha and T18 oncoproteins. Nature Genet. 23: 287-295, 1999. [PubMed: 10610177] [Full Text: https://doi.org/10.1038/15463]