A Functional Genetic Screen Identifies TFE3 as a Gene That Confers Resistance to the Anti-proliferative Effects of the Retinoblastoma Protein and Transforming Growth Factor-β

Abstract

The helix-loop-helix transcription factor TFE3 has been suggested to play a role in the control of cell growth by acting as a binding partner of transcriptional regulators such as E2F3, SMAD3, and LEF-1 (1Hua X. Liu X. Ansari D.O. Lodish H.F. Genes Dev. 1998; 12: 3084-3095Crossref PubMed Scopus (261) Google Scholar, 2Yasumoto K. Takeda K. Saito H. Watanabe K. Takahashi K. Shibahara S. EMBO J. 2002; 21: 2703-2714Crossref PubMed Scopus (192) Google Scholar, 3Giangrande P.H. Zhu W. Rempel R.E. Laakso N. Nevins J.R. EMBO J. 2004; 23: 1336-1347Crossref PubMed Scopus (68) Google Scholar, 4Giangrande P.H. Hallstrom T.C. Tunyaplin C. Calame K. Nevins J.R. Mol. Cell. Biol. 2003; 23: 3707-3720Crossref PubMed Scopus (91) Google Scholar). Furthermore, translocations/TFE3 fusions have been directly implicated in tumorigenesis (5Weterman M.A. Wilbrink M. Geurts van Kessel A. Proc. Natl. Acad. Sci. U. S. A. 1996; 93: 15294-15298Crossref PubMed Scopus (192) Google Scholar, 6Sidhar S.K. Clark J. Gill S. Hamoudi R. Crew A.J. Gwilliam R. Ross M. Linehan W.M. Birdsall S. Shipley J. Cooper C.S. Hum. Mol. Genet. 1996; 5: 1333-1338Crossref PubMed Scopus (241) Google Scholar, 7Argani P. Antonescu C.R. Illei P.B. Lui M.Y. Timmons C.F. Newbury R. Reuter V.E. Garvin A.J. Perez-Atayde A.R. Fletcher J.A. Beckwith J.B. Bridge J.A. Ladanyi M. Am. J. Pathol. 2001; 159: 179-192Abstract Full Text Full Text PDF PubMed Scopus (558) Google Scholar). Surprisingly, however, a direct functional role for TFE3 in the regulation of proliferation has not been reported. By screening retroviral cDNA expression libraries to identify cDNAs that confer resistance to a pRB-induced proliferation arrest, we have found that TFE3 overrides a growth arrest in Rat1 cells induced by pRB and its upstream regulator p16INK4A. In addition, TFE3 expression blocks the anti-mitogenic effects of TGF-β in rodent and human cells. We provide data supporting a role for endogenous TFE3 in the direct regulation of CYCLIN E expression in an E2F3-dependent manner. These observations establish TFE3 as a functional regulator of proliferation and offer a potential mechanism for its involvement in cancer. The helix-loop-helix transcription factor TFE3 has been suggested to play a role in the control of cell growth by acting as a binding partner of transcriptional regulators such as E2F3, SMAD3, and LEF-1 (1Hua X. Liu X. Ansari D.O. Lodish H.F. Genes Dev. 1998; 12: 3084-3095Crossref PubMed Scopus (261) Google Scholar, 2Yasumoto K. Takeda K. Saito H. Watanabe K. Takahashi K. Shibahara S. EMBO J. 2002; 21: 2703-2714Crossref PubMed Scopus (192) Google Scholar, 3Giangrande P.H. Zhu W. Rempel R.E. Laakso N. Nevins J.R. EMBO J. 2004; 23: 1336-1347Crossref PubMed Scopus (68) Google Scholar, 4Giangrande P.H. Hallstrom T.C. Tunyaplin C. Calame K. Nevins J.R. Mol. Cell. Biol. 2003; 23: 3707-3720Crossref PubMed Scopus (91) Google Scholar). Furthermore, translocations/TFE3 fusions have been directly implicated in tumorigenesis (5Weterman M.A. Wilbrink M. Geurts van Kessel A. Proc. Natl. Acad. Sci. U. S. A. 1996; 93: 15294-15298Crossref PubMed Scopus (192) Google Scholar, 6Sidhar S.K. Clark J. Gill S. Hamoudi R. Crew A.J. Gwilliam R. Ross M. Linehan W.M. Birdsall S. Shipley J. Cooper C.S. Hum. Mol. Genet. 1996; 5: 1333-1338Crossref PubMed Scopus (241) Google Scholar, 7Argani P. Antonescu C.R. Illei P.B. Lui M.Y. Timmons C.F. Newbury R. Reuter V.E. Garvin A.J. Perez-Atayde A.R. Fletcher J.A. Beckwith J.B. Bridge J.A. Ladanyi M. Am. J. Pathol. 2001; 159: 179-192Abstract Full Text Full Text PDF PubMed Scopus (558) Google Scholar). Surprisingly, however, a direct functional role for TFE3 in the regulation of proliferation has not been reported. By screening retroviral cDNA expression libraries to identify cDNAs that confer resistance to a pRB-induced proliferation arrest, we have found that TFE3 overrides a growth arrest in Rat1 cells induced by pRB and its upstream regulator p16INK4A. In addition, TFE3 expression blocks the anti-mitogenic effects of TGF-β in rodent and human cells. We provide data supporting a role for endogenous TFE3 in the direct regulation of CYCLIN E expression in an E2F3-dependent manner. These observations establish TFE3 as a functional regulator of proliferation and offer a potential mechanism for its involvement in cancer. During cell cycle progression, the retinoblastoma pocket protein (pRB) 2The abbreviations used are: pRB, retinoblastoma pocket protein; GFP, green fluorescent protein; MEF, mouse embryo fibroblast. is phosphorylated by upstream cyclin-CDK complexes, ultimately leading to activation of genes critical for cell division. Extensive study of pRB has indicated that it serves as a nodal point for the integration of various signaling pathways, including TGF-β and p16INK4A signaling, in controlling cell growth (8Vogelstein B. Kinzler K.W. Nat. Med. 2004; 10: 789-799Crossref PubMed Scopus (3403) Google Scholar, 9Harbour J.W. Dean D.C. Genes Dev. 2000; 14: 2393-2409Crossref PubMed Scopus (974) Google Scholar). Numerous mutations in the retinoblastoma gene itself have been reported, and somatic ablation in mouse embryo fibroblasts is sufficient for cell cycle entry (10Sage J. Miller A.L. Perez-Mancera P.A. Wysocki J.M. Jacks T. Nature. 2003; 424: 223-228Crossref PubMed Scopus (450) Google Scholar). In addition, in many tumors, the INK4A locus is found inactivated, leading to uninhibited phosphorylation of pRB due to loss of the p16INK4A CDK inhibitor. Alternatively, cancer cells overexpress upstream inhibitors of the growth-suppressive effects of pRB, such as D-type cyclins. Indeed, detailed analysis of the pRB pathway indicates that functional inactivation of pRB is a requirement for the multistep process toward tumorigenesis. Furthermore, it is likely that other genetic aberrations resulting in defects in pRB function remain to be discovered. The activity of the transcription factors E2F1, -2, and -3 is actively repressed by pRB, and this is thought to represent the most important role of pRB in S-phase entry, DNA replication, and apoptosis (11Attwooll C. Lazzerini Denchi E. Helin K. EMBO J. 2004; 23: 4709-4716Crossref PubMed Scopus (430) Google Scholar, 12Frolov M.V. Dyson N.J. J. Cell Sci. 2004; 117: 2173-2181Crossref PubMed Scopus (335) Google Scholar). The central part that these E2Fs play in cell cycle regulation is emphasized by the finding that enforced expression of E2F1 alone is sufficient to mediate S-phase entry, whereas genetic ablation of all three pRB-interacting E2Fs leads to a proliferation arrest (13Wu L. Timmers C. Maiti B. Saavedra H.I. Sang L. Chong G.T. Nuckolls F. Giangrande P. Wright F.A. Field S.J. Greenberg M.E. Orkin S. Nevins J.R. Robinson M.L. Leone G. Nature. 2001; 414: 457-462Crossref PubMed Scopus (505) Google Scholar, 14Johnson D.G. Schwarz J.K. Cress W.D. Nevins J.R. Nature. 1993; 365: 349-352Crossref PubMed Scopus (850) Google Scholar). Nonetheless, no strong evidence supports a direct oncogenic role for E2Fs. Repression of E2F1–3 target genes by pRB is achieved in a number of distinct ways (12Frolov M.V. Dyson N.J. J. Cell Sci. 2004; 117: 2173-2181Crossref PubMed Scopus (335) Google Scholar). First, pRB binds directly to the transactivation domains of the E2Fs, blocking their activity. In addition, pRB promoter binding prevents the assembly of preinitiation factors, thereby inhibiting the action of adjacent transcription factors. Finally, pRB recruits chromatin modification and remodeling factors, such as HDACs, BRG1, and hBRM, which promote heterochromatin formation and promote long term gene silencing (15Zhang H.S. Gavin M. Dahiya A. Postigo A.A. Ma D. Luo R.X. Harbour J.W. Dean D.C. Cell. 2000; 101: 79-89Abstract Full Text Full Text PDF PubMed Scopus (544) Google Scholar, 16Dunaief J.L. Strober B.E. Guha S. Khavari P.A. Alin K. Luban J. Begemann M. Crabtree G.R. Goff S.P. Cell. 1994; 79: 119-130Abstract Full Text PDF PubMed Scopus (558) Google Scholar). Analysis of single and compound E2F1–3 knock-out mice has revealed redundant (but also unique) roles for the various E2Fs. For instance, E2F3 appears to play a critical role in maintaining proliferation by repressing p19ARF transcription, a potent activator of p53 (17Aslanian A. Iaquinta P.J. Verona R. Lees J.A. Genes Dev. 2004; 18: 1413-1422Crossref PubMed Scopus (154) Google Scholar). Because E2F1–3 regulate overlapping (but also distinct) genes, these functional differences are likely because of differences in target gene specificity. The mechanisms for E2F target specificity are not well understood but may involve recruitment of specific co-factors. For example, E2F1 (but not E2F2/3) binds to the ETS-related transcription factor GABP-γ1, whereas YY1 specifically interacts with E2F2/3 (18Schlisio S. Halperin T. Vidal M. Nevins J.R. EMBO J. 2002; 21: 5775-5786Crossref PubMed Scopus (178) Google Scholar, 19Hauck L. Kaba R.G. Lipp M. Dietz R. von Harsdorf R. Mol. Cell. Biol. 2002; 22: 2147-2158Crossref PubMed Scopus (26) Google Scholar). The basic helix-loop-helix transcription factor TFE3 and its close family member USF1 were recently found to specifically interact with E2F3, thereby regulating target promoters containing adjacent E2F and TFE3 binding sites (3Giangrande P.H. Zhu W. Rempel R.E. Laakso N. Nevins J.R. EMBO J. 2004; 23: 1336-1347Crossref PubMed Scopus (68) Google Scholar, 4Giangrande P.H. Hallstrom T.C. Tunyaplin C. Calame K. Nevins J.R. Mol. Cell. Biol. 2003; 23: 3707-3720Crossref PubMed Scopus (91) Google Scholar). TFE3 was originally identified by its affinity for an E-box in the immunoglobulin heavy chain enhancer element and later as a co-factor in a number of signal transduction pathways (20Beckmann H. Su L.K. Kadesch T. Genes Dev. 1990; 4: 167-179Crossref PubMed Scopus (354) Google Scholar). For instance, TFE3 and its family member, MitF, bind to the Wnt transcription factor LEF-1 and cooperate to induce dopachrome tautomerase transcription (2Yasumoto K. Takeda K. Saito H. Watanabe K. Takahashi K. Shibahara S. EMBO J. 2002; 21: 2703-2714Crossref PubMed Scopus (192) Google Scholar). In addition, TFE3 cooperates with ETS-1, and TFE3 has been found to bind SMAD3 and SMAD4 and synergistically transactivate PAI-1 transcription in response to TGF-β, a feature that may be shared with some of the TFE3 fusions found in cancer (1Hua X. Liu X. Ansari D.O. Lodish H.F. Genes Dev. 1998; 12: 3084-3095Crossref PubMed Scopus (261) Google Scholar, 21Tian G. Erman B. Ishii H. Gangopadhyay S.S. Sen R. Mol. Cell. Biol. 1999; 19: 2946-2957Crossref PubMed Scopus (45) Google Scholar, 22Rao E. Dang W. Tian G. Sen R. J. Biol. Chem. 1997; 272: 6722-6732Abstract Full Text Full Text PDF PubMed Scopus (48) Google Scholar, 23Skalsky Y.M. Ajuh P.M. Parker C. Lamond A.I. Goodwin G. Cooper C.S. Oncogene. 2001; 20: 178-187Crossref PubMed Scopus (56) Google Scholar). Importantly, however, these studies have been mostly limited to biochemical and molecular studies and consequently have failed to define a role for TFE3 in proliferation. Indeed, despite the observation that many of the binding partners of TFE3 play a critical role in proliferation, a cellular function of TFE3 has not been determined. In the present study, we set out to find new mechanisms by which cells can become insensitive to the p16-cyclin D-pRB pathway. More specifically, we looked for genes that allow proliferation in the presence of hypophosphorylated pRB by enforcing a strong growth-inhibitory block using a dominant active pRB mutant. We now have established TFE3 as a gene that can uncouple cell cycle progression from pRB phosphorylation and TGF-β signaling and identify a functional role for TFE3 in regulating CYCLIN E expression. Generation of Cells to Screen for cDNAs That Confer Resistance to pRB-induced Growth Arrest—Rat1 fibroblasts were transfected at 32 °C with pcDNA3.1-tsT, expressing tsT antigen (see Fig. 1a) (24Lee G.H. Ogawa K. Drinkwater N.R. Am. J. Pathol. 1995; 147: 1811-1822PubMed Google Scholar). G418-resistant colonies were assayed for the expression of the large T antigen by Western blot analysis. Clone C5 was then transfected with the pRB-NPC expression vector or with the p16-GFP expression vector. The pRB-NPC protein harbors an amino-terminal GFP tag to allow continuous monitoring of the presence of the growth-inhibitory RB protein in individual cells. A stable colony of pRB-NPC-transfected cells having the lowest number of spontaneous background colonies at the non-permissive temperature (39 °C) was chosen for the functional genetic screens (named Rat1 C5.5). Similarly, a stable colony from the p16-GFP transfection was selected with low spontaneous background (termed Rat1 C5A). Retroviral Rescue Screens—High titer retroviral library supernatants derived from human brain (Clontech) were used to infect 4–5 × 106 Rat1 C5.5 cells at 32 °C as described previously (25Berns K. Hijmans E.M. Koh E. Daley G.Q. Bernards R. Oncogene. 2000; 19: 3330-3334Crossref PubMed Scopus (52) Google Scholar). Two days post-infection, the cells were split 1 in 12, allowed to attach at 32 °C, and then transferred to 39 °C. Several individual colonies were visible as soon as 8 days after the temperature shift. The colonies were picked and expanded. Recovery of integrated proviruses for the second round selection has been described previously (26Jacobs J.J. Keblusek P. Robanus-Maandag E. Kristel P. Lingbeek M. Nederlof P.M. van Welsem T. van de Vijver M.J. Koh E.Y. Daley G.Q. van Lohuizen M. Nat. Genet. 2000; 26: 291-299Crossref PubMed Scopus (324) Google Scholar). After the second round selection, retrovirally encoded cDNAs were recovered by PCR with retrovirus-specific primers and identified by sequence analysis (25Berns K. Hijmans E.M. Koh E. Daley G.Q. Bernards R. Oncogene. 2000; 19: 3330-3334Crossref PubMed Scopus (52) Google Scholar). Western Blotting—Cell extracts were prepared in E1A lysis buffer (ELB), and 40–60 μg of extract was resolved were transferred to used for Western were for for pRB, for for for for for and for all from The was used for the of T was used for the of or E2F3 knock-out were by with a the large T antigen Verona R. J.M. C. S. Lees J.A. Genes Dev. 2000; 14: PubMed Google Scholar). cells were used for chromatin and as described E. S. J. C. J.R. M. S. A. C. EMBO 2002; PubMed Scopus Google Scholar, A.J. C. R.E. Mol. Cell. Biol. 2002; 22: PubMed Scopus Google Scholar). E and primers were as E. S. J. C. J.R. M. S. A. C. EMBO 2002; PubMed Scopus Google Scholar). TFE3 was from A for of a Growth for genes confer resistance to the growth activity of pRB, we used a functional genetic We transfected the Rat1 cell with a of T antigen The tsT antigen binds and pRB at the temperature °C) but is and at 39 °C (see Fig. second from (24Lee G.H. Ogawa K. Drinkwater N.R. Am. J. Pathol. 1995; 147: 1811-1822PubMed Google Scholar). A expressing of tsT was selected and transfected at the temperature with a active of pRB M. S. S. Oncogene. 1998; PubMed Scopus Google Scholar). pRB in which of the CDK phosphorylation sites have been to has strong in the presence of CDK a cell cycle block in the cells at the temperature pRB-NPC is due to its binding to the T expressing pRB-NPC were picked and selected for growth arrest at 39 °C. of the at 32 °C but proliferation at 39 °C The in cell proliferation at 39 °C with a in protein of the E2F target genes and Retroviral of a protein of pRB, allowed some of the cells to proliferation at 39 °C The by E1A of the pRB growth arrest may be due to the of apoptosis by We at 39 °C, the cells a cell cycle arrest that is we the cells at 32 °C with a retroviral cDNA expression library derived from human brain or a control expressing after the cells were and selected for colony at 39 °C. Several colonies of cells visible after in the cDNA the colonies the were because of a retrovirally encoded the colonies were with to integrated proviruses (26Jacobs J.J. Keblusek P. Robanus-Maandag E. Kristel P. Lingbeek M. Nederlof P.M. van Welsem T. van de Vijver M.J. Koh E.Y. Daley G.Q. van Lohuizen M. Nat. Genet. 2000; 26: 291-299Crossref PubMed Scopus (324) Google Scholar). Two days containing was from the colonies and used to infect cells. derived from of the a number of colonies in second round and these colonies were encoded cDNAs were recovered using PCR and identified by DNA sequence analysis (25Berns K. Hijmans E.M. Koh E. Daley G.Q. Bernards R. Oncogene. 2000; 19: 3330-3334Crossref PubMed Scopus (52) Google Scholar). colonies were found to a cDNA for the basic helix-loop-helix transcription factor TFE3 (20Beckmann H. Su L.K. Kadesch T. Genes Dev. 1990; 4: 167-179Crossref PubMed Scopus (354) Google Scholar). provide evidence that TFE3 the pRB-induced proliferation arrest, we the TFE3 cDNA in a retroviral vector and cells. TFE3 the arrest at 39 °C We that TFE3 Rat1 cells insensitive for the growth-inhibitory effects of TFE3 Cells for p16INK4A and we TFE3 also cells from a growth arrest endogenous First, we TFE3 growth arrest induced by as this the presence of functional pRB J. D. L. J. M. G. J. Nature. 1995; PubMed Scopus Google Scholar, R.E. F. Proc. Natl. Acad. Sci. U. S. A. 1995; PubMed Scopus Google Scholar). we used a second of of a to the this at 32 °C but proliferation at 39 °C Retroviral transduction of these cells with TFE3 and selection for colony at 39 °C many colonies expressing as by and data not TFE3 has been implicated in TGF-β signaling by with SMAD3 and SMAD4 to target genes (1Hua X. Liu X. Ansari D.O. Lodish H.F. Genes Dev. 1998; 12: 3084-3095Crossref PubMed Scopus (261) Google Scholar, X. Miller H. J.L. Lodish H.F. J. Biol. Chem. 2000; Full Text Full Text PDF PubMed Scopus Google Scholar). the functional of this potential TGF-β role of TFE3 have Furthermore, the action of TGF-β the presence of functional pRB J.A. E. P. R. K. P.M. Cell. 1990; Full Text PDF PubMed Scopus Google Scholar, R.E. Mol. Biol. Cell. 1996; PubMed Scopus (68) Google Scholar, A. P.H. H. T. M.L. Nature. 1996; PubMed Scopus Google Scholar, J.K. M. S. Nevins J.R. Proc. Natl. Acad. Sci. U. S. A. 1995; PubMed Scopus Google Scholar). also the in to the expression of TGF-β target genes, TFE3 confer resistance to TGF-β we used as these cells are to the effects of cells were with or control to TGF-β days post-infection, and proliferation was in TFE3 strong resistance to growth whereas proliferation of cells was by and were in cells and human other cell not the that TFE3 can cells insensitive to growth-inhibitory that endogenous TFE3 E in an E2F3-dependent to the mechanism TFE3 cell cycle progression from pRB we TFE3 with the of specific E2F target We cells and at 32 °C and prepared cell and days after to the temperature (39 temperature of control cells a in the protein of the E2F target genes and and to a A other and these in the E were at 32 °C. 39 °C, expression of E was repressed but in cells at 32 °C. was specific for because cells not of E not it was that TFE3 and E2F3 bind to a of E2F target genes, thereby synergistically transcription (3Giangrande P.H. Zhu W. Rempel R.E. Laakso N. Nevins J.R. EMBO J. 2004; 23: 1336-1347Crossref PubMed Scopus (68) Google Scholar, 4Giangrande P.H. Hallstrom T.C. Tunyaplin C. Calame K. Nevins J.R. Mol. Cell. Biol. 2003; 23: 3707-3720Crossref PubMed Scopus (91) Google Scholar). we to E2F3 and TFE3 can cooperate to the human CYCLIN E For this we the effects of these transcription factors a to CYCLIN the of expression vector TFE3 alone the CYCLIN E whereas expression of E2F3 the Importantly, of TFE3 and E2F3 to a activation of the CYCLIN E gene that TFE3 and E2F3 can cooperate to the CYCLIN E Finally, we TFE3 can bind to the E promoter in and this is the presence of We chromatin analysis with TFE3 in cells expressing and E2F3 PCR analysis of chromatin from revealed that endogenous TFE3 is to the E promoter but not to a control promoter Importantly, the binding of endogenous TFE3 to be the presence of E2F3, because TFE3 was to the E promoter in cells We that TFE3 E expression and that E2F3 is for endogenous TFE3 binding to the E We have identified TFE3 as a potent of from the and TGF-β in Rat1 TFE3 resistance to p16INK4A and we were to activity in human fibroblasts not Nonetheless, TFE3 resistance to growth arrest in human and rodent that at some of the of TFE3 are Because a TGF-β growth arrest the presence of pRB, it is to that TFE3 resistance to TGF-β signaling by with the of pRB target genes J.A. E. P. R. K. P.M. Cell. 1990; Full Text PDF PubMed Scopus Google Scholar, R.E. Mol. Biol. Cell. 1996; PubMed Scopus (68) Google Scholar, A. P.H. H. T. M.L. Nature. 1996; PubMed Scopus Google Scholar, J.K. M. S. Nevins J.R. Proc. Natl. Acad. Sci. U. S. A. 1995; PubMed Scopus Google Scholar). TFE3 was also to with TGF-β in target genes, the protein X. Miller H. J.L. Lodish H.F. J. Biol. Chem. 2000; Full Text Full Text PDF PubMed Scopus Google Scholar). this that TFE3 can be an enhancer of TGF-β signaling and an of cell cycle was recently found that TFE3 and its close family member, bind specifically to E2F3, resulting in activation of E2F target promoters (3Giangrande P.H. Zhu W. Rempel R.E. Laakso N. Nevins J.R. EMBO J. 2004; 23: 1336-1347Crossref PubMed Scopus (68) Google Scholar, 4Giangrande P.H. Hallstrom T.C. Tunyaplin C. Calame K. Nevins J.R. Mol. Cell. Biol. 2003; 23: 3707-3720Crossref PubMed Scopus (91) Google Scholar). A was in which adjacent E2F binding sites and in a promoter allow the binding of resulting in transcriptional In with a role for TFE3 in regulating CYCLIN E transcription, we found that Rat1 cells of CYCLIN TFE3 and E2F3 synergistically a CYCLIN E and endogenous TFE3 binds to the E promoter in an E2F3-dependent manner. recruitment of the CYCLIN E promoter to the resistance to and TGF-β Several studies have suggested that CYCLIN E expression can control S-phase entry of the pRB phosphorylation J. T. K. D. Helin K. J. Genes Dev. 1997; PubMed Scopus Google Scholar, K. J. S. B. EMBO J. 1997; PubMed Scopus Google Scholar). of CYCLIN E not cell cycle arrest by the pRB-NPC used M. S. S. Oncogene. 1998; PubMed Scopus Google Scholar). In with we were to pRB-NPC growth arrest in cells expression of CYCLIN E not More TFE3 transcriptional to cells insensitive to and some of these may be by Indeed, because TFE3 as a co-factor for a number of transcription factors, it is that of TFE3 to the of a pRB-induced growth For instance, TFE3 (but not its close family member binds to the transcription a role of TFE3 in the cell cycle G. Erman B. Ishii H. Gangopadhyay S.S. Sen R. Mol. Cell. Biol. 1999; 19: 2946-2957Crossref PubMed Scopus (45) Google Scholar). In with a function of TFE3 in regulating proliferation, a in S-phase entry after H. Giangrande and J. R. The mechanisms TFE3 a cell cycle arrest are and Nonetheless, this study TFE3 as a protein that can uncouple cell cycle progression from pRB phosphorylation and a potential mechanism for its role in tumorigenesis. We for the of the pRB Drinkwater for the tsT antigen Helin for E2F3 and Lees for We and for with some of the for critical and of the Bernards for