BTG2

Protein BTG2 also known as BTG family member 2 or NGF-inducible anti-proliferative protein PC3 or NGF-inducible protein TIS21, is a protein that in humans is encoded by the BTG2 gene (B-cell translocation gene 2)[4] and in other mammals by the homologous Btg2 gene.[5][6] This protein controls cell cycle progression and proneural genes expression by acting as a transcription coregulator that enhances or inhibits the activity of transcription factors.

BTG2
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 3DJU, 3E9V
Identifiers
Aliases	BTG2, PC3, TIS21, BTG family member 2, BTG anti-proliferation factor 2, APRO1
External IDs	OMIM: 601597 MGI: 108384 HomoloGene: 31406 GeneCards: BTG2
Gene location (Human) Chr. Chromosome 1 (human)[1] Band 1q32.1 Start 203,305,491 bp[1] End 203,309,602 bp[1]
RNA expression pattern More reference expression data
Gene ontology Molecular function • GO:0001078, GO:0001214, GO:0001206 DNA-binding transcription repressor activity, RNA polymerase II-specific • GO:0001948 protein binding Cellular component • extracellular exosome • cytosol • cell nucleus • cytoplasm Biological process • negative regulation of neuron apoptotic process • negative regulation of translation • positive regulation of nuclear-transcribed mRNA poly(A) tail shortening • associative learning • regulation of transcription, DNA-templated • response to organic cyclic compound • dentate gyrus development • negative regulation of neural precursor cell proliferation • response to mechanical stimulus • response to peptide hormone • negative regulation of apoptotic process • negative regulation of transcription from RNA polymerase II promoter • response to electrical stimulus • response to organic substance • transcription, DNA-templated • cellular response to DNA damage stimulus • central nervous system neuron development • response to organonitrogen compound • neuron differentiation • skeletal muscle cell differentiation • neuron projection development • DNA repair • anterior/posterior pattern specification • protein methylation • negative regulation of cell proliferation • DNA damage response, signal transduction by p53 class mediator resulting in cell cycle arrest • negative regulation of mitotic cell cycle Sources:Amigo / QuickGO
Orthologs
Species	Human	Mouse
Entrez	7832	12227
Ensembl	ENSG00000159388	n/a
UniProt	P78543	Q04211
RefSeq (mRNA)	NM_006763	NM_007570
RefSeq (protein)	NP_006754	NP_031596
Location (UCSC)	Chr 1: 203.31 – 203.31 Mb	n/a
PubMed search	[2]	[3]
Wikidata
View/Edit Human View/Edit Mouse

The protein BTG2 is the human homolog of the PC3 (pheochromocytoma cell 3) protein in rat and of the Tis21 (tetradecanoyl phorbol acetate-inducible sequence 21) protein in mouse.[7][8] Tis21 had been originally isolated as a sequence induced by TPA in mouse fibroblasts,[6] whereas PC3 was originally isolated as sequence induced at the beginning of neuron differentiation;[5] BTG2 was then isolated in human cells as sequence induced by p53 and DNA damage.[4][9]

The protein encoded by the gene BTG2 (which is the official name assigned to the gene PC3/Tis21/BTG2) is a member of the BTG/Tob family (that comprises six proteins BTG1, BTG2/PC3/Tis21, BTG3/ANA, BTG4/PC3B, Tob1/Tob and Tob2).[7][8][10] This family has structurally related proteins that appear to have antiproliferative properties. In particular, the BTG2 protein has been shown to negatively control a cell cycle checkpoint at the G₁ to S phase transition in fibroblasts and neuronal cells by direct inhibition of the activity of cyclin D1 promoter.[11][12][13]

Regulator of neuron differentiation

A number of studies in vivo have shown that BTG2 expression is associated with the neurogenic asymmetric division in neural progenitor cells.[14][15][16][17][18] Moreover, when directly overexpressed in vivo in neural progenitor cells, BTG2 induces their differentiation.[19][20] In fact, in the neuronal PC12 cell line BTG2 is not able to trigger differentiation by itself, but only to synergize with NGF,[21][22] while in vivo BTG2 is fully able to induce differentiation of progenitor cells, i.e., during embryonic development in the neuroblast of the neural tube and in granule precursors of cerebellum, as well in adult progenitor cells of the dentate gyrus and of the subventricular zone.[19][20] Notably, it has recently been shown that BTG2 is essential for the differentiation of new neurons, using a BTG2 knock out mouse.[23] BTG2 is thus a pan-neural gene required for the development of the new neuron generated during adulthood, in the two neurogenic regions of adult brain, i.e., the hippocampus and the subventricular zone.[23] Such requirement of BTG2 in neuron maturation is consistent with the fact that during brain development BTG2 is expressed in the proliferating neuroblasts of the ventricular zone of the neural tube, and to a lower extent in the differentiating neuroblasts of the mantle zone; postnatally it is expressed in cerebellar precursors mainly in the proliferating regions of the neuropithelium (i.e., in the external granular layer), and in the hippocampus in proliferating and differentiating progenitor cells.[14][19][20] The pro-differentiative action of BTG2 appears to be consequent not only to inhibition of cell cycle progression but also to a BTG2-dependent activation of proneural genes in neural progenitor cells.[19][23] In fact, BTG2 activates proneural genes by associating with the promoter of Id3, a key inhibitor of proneural gene activity, and by negatively regulating its activity.[23]

BTG2 is a transcriptional cofactor, given that it has been shown to associate with, and regulate the promoters not only of Id3 but also of cyclin D1 and RAR-β, being part of transcriptional complexes.[13][24][25] It has been shown that when the differentiation of new neurons of the hippocampus - a brain region important for learning and memory - is either accelerated or delayed by means of overexpression or deletion of BTG2, respectively, spatial and contextual memory is heavily altered.[20][23] This suggests that the time the young neurons spend in different states of neuronal differentiation is critical for their ultimate function in learning and memory, and that BTG2 may play a role in the timing of recruitment of the new neuron into memory circuits.[20][23]

In conclusion, the main action of Btg2 on neural progenitor cells of the dentate gyrus and subventricular zone during adult neurogenesis is the positive control of their terminal differentiation (see for review:[26]). During the early postnatal development of the cerebellum, Btg2 is mainly required to control the migration and differentiation of the precursor cells of cerebellar granule neurons.[27] In contrast, BTG1, the closest homolog to Btg2, appears to negatively regulate the proliferation of adult stem cells in the dentate gyrus and subventricular zone, maintaining in quiescence the stem cells pool and preserving it from depletion.[28][29] BTG1 is also necessary to limit the proliferative expansion of cerebellar precursor cells, as without BTG1 the adult cerebellum is larger and unable to coordinate motor activity.[30]

Medulloblastoma suppressor

BTG2 has been shown to inhibit medulloblastoma, the very aggressive tumor of cerebellum, by inhibiting the proliferation and triggering the differentiation of the precursors of cerebellar granule neurons. This demonstration was obtained by overexpressing BTG2 in a mouse model of medulloblastoma, presenting activation of the sonic hedgehog pathway (heterozygous for the gene Patched1).[13] More recently, it has been shown that the ablation of BTG2 greatly enhances the medulloblastoma frequency by inhibiting the migration of cerebellar granule neuron precursors. This impairment of migration of the precursors of cerebellar granule neurons forces them to remain at the surface of the cerebellum, where they continue to proliferate, becoming target of transforming insults.[31] The impairment of migration of the precursors of cerebellar granule neurons (GCPs) depends on the inhibition of expression of the chemokine CXCL3 consequent to ablation of BTG2. In fact, the transcription of CXCL3 is directly regulated by BTG2, and CXCL3 is able to induce cell-autonomously the migration of cerebellar granule precursors. Treatment with CXCL3 prevents the growth of medulloblastoma lesions in a Shh-type mouse model of medulloblastoma.[32] Thus, CXCL3 is a target for medulloblastoma therapy.[31][32]

Interactions

BTG2 has been shown to interact with PRMT1,[25] HOXB9,[33][34] CNOT8[35] and HDAC1 HDAC4 and HDAC9.[36][13]

References

1. GRCh38: Ensembl release 89: ENSG00000159388 - Ensembl, May 2017
2. "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
3. "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
4. Rouault JP, Falette N, Guéhenneux F, Guillot C, Rimokh R, Wang Q, Berthet C, Moyret-Lalle C, Savatier P, Pain B, Shaw P, Berger R, Samarut J, Magaud JP, Ozturk M, Samarut C, Puisieux A (December 1996). "Identification of BTG2, an antiproliferative p53-dependent component of the DNA damage cellular response pathway". Nature Genetics. 14 (4): 482–6. doi:10.1038/ng1296-482. hdl:11693/49026. PMID 8944033.
5. Bradbury A, Possenti R, Shooter EM, Tirone F (April 1991). "Molecular cloning of PC3, a putatively secreted protein whose mRNA is induced by nerve growth factor and depolarization". Proceedings of the National Academy of Sciences of the United States of America. 88 (8): 3353–7. doi:10.1073/pnas.88.8.3353. PMC 51445. PMID 1849653.
6. Fletcher BS, Lim RW, Varnum BC, Kujubu DA, Koski RA, Herschman HR (August 1991). "Structure and expression of TIS21, a primary response gene induced by growth factors and tumor promoters". The Journal of Biological Chemistry. 266 (22): 14511–8. PMID 1713584.
7. Matsuda S, Rouault J, Magaud J, Berthet C (May 2001). "In search of a function for the TIS21/PC3/BTG1/TOB family". FEBS Letters. 497 (2–3): 67–72. doi:10.1016/S0014-5793(01)02436-X. PMID 11377414.
8. Tirone F (May 2001). "The gene PC3(TIS21/BTG2), prototype member of the PC3/BTG/TOB family: regulator in control of cell growth, differentiation, and DNA repair?". Journal of Cellular Physiology. 187 (2): 155–65. doi:10.1002/jcp.1062. PMID 11267995.
9. "Entrez Gene: BTG2 BTG family, member 2".
10. Winkler GS (January 2010). "The mammalian anti-proliferative BTG/Tob protein family". Journal of Cellular Physiology. 222 (1): 66–72. doi:10.1002/jcp.21919. PMID 19746446.
11. Montagnoli A, Guardavaccaro D, Starace G, Tirone F (October 1996). "Overexpression of the nerve growth factor-inducible PC3 immediate early gene is associated with growth inhibition". Cell Growth & Differentiation. 7 (10): 1327–36. PMID 8891336.
12. Guardavaccaro D, Corrente G, Covone F, Micheli L, D'Agnano I, Starace G, Caruso M, Tirone F (March 2000). "Arrest of G(1)-S progression by the p53-inducible gene PC3 is Rb dependent and relies on the inhibition of cyclin D1 transcription". Molecular and Cellular Biology. 20 (5): 1797–815. doi:10.1128/MCB.20.5.1797-1815.2000. PMC 85361. PMID 10669755.
13. Farioli-Vecchioli S, Tanori M, Micheli L, Mancuso M, Leonardi L, Saran A, Ciotti MT, Ferretti E, Gulino A, Pazzaglia S, Tirone F (July 2007). "Inhibition of medulloblastoma tumorigenesis by the antiproliferative and pro-differentiative gene PC3" (PDF). FASEB Journal. 21 (9): 2215–25. doi:10.1096/fj.06-7548com. PMID 17371797.
14. Iacopetti P, Barsacchi G, Tirone F, Maffei L, Cremisi F (August 1994). "Developmental expression of PC3 gene is correlated with neuronal cell birthday" (PDF). Mechanisms of Development. 47 (2): 127–37. doi:10.1016/0925-4773(94)90085-X. PMID 7811636. Archived from the original (PDF) on 2011-07-22.
15. Iacopetti P, Michelini M, Stuckmann I, Oback B, Aaku-Saraste E, Huttner WB (April 1999). "Expression of the antiproliferative gene TIS21 at the onset of neurogenesis identifies single neuroepithelial cells that switch from proliferative to neuron-generating division". Proceedings of the National Academy of Sciences of the United States of America. 96 (8): 4639–44. doi:10.1073/pnas.96.8.4639. PMC 16385. PMID 10200315.
16. Haubensak W, Attardo A, Denk W, Huttner WB (March 2004). "Neurons arise in the basal neuroepithelium of the early mammalian telencephalon: a major site of neurogenesis". Proceedings of the National Academy of Sciences of the United States of America. 101 (9): 3196–201. doi:10.1073/pnas.0308600100. PMC 365766. PMID 14963232.
17. Calegari F, Haubensak W, Haffner C, Huttner WB (July 2005). "Selective lengthening of the cell cycle in the neurogenic subpopulation of neural progenitor cells during mouse brain development". The Journal of Neuroscience. 25 (28): 6533–8. doi:10.1523/JNEUROSCI.0778-05.2005. PMC 6725437. PMID 16014714.
18. Götz M, Huttner WB (October 2005). "The cell biology of neurogenesis". Nature Reviews Molecular Cell Biology. 6 (10): 777–88. doi:10.1038/nrm1739. PMID 16314867.
19. Canzoniere D, Farioli-Vecchioli S, Conti F, Ciotti MT, Tata AM, Augusti-Tocco G, Mattei E, Lakshmana MK, Krizhanovsky V, Reeves SA, Giovannoni R, Castano F, Servadio A, Ben-Arie N, Tirone F (March 2004). "Dual control of neurogenesis by PC3 through cell cycle inhibition and induction of Math1". The Journal of Neuroscience. 24 (13): 3355–69. doi:10.1523/JNEUROSCI.3860-03.2004. PMC 6730030. PMID 15056715.
20. Farioli-Vecchioli S, Saraulli D, Costanzi M, Pacioni S, Cinà I, Aceti M, Micheli L, Bacci A, Cestari V, Tirone F (October 2008). "The timing of differentiation of adult hippocampal neurons is crucial for spatial memory". PLoS Biology. 6 (10): e246. doi:10.1371/journal.pbio.0060246. PMC 2561078. PMID 18842068.
21. Corrente G, Guardavaccaro D, Tirone F (March 2002). "PC3 potentiates NGF-induced differentiation and protects neurons from apoptosis" (PDF). NeuroReport. 13 (4): 417–22. doi:10.1097/00001756-200203250-00011. PMID 11930152.
22. el-Ghissassi F, Valsesia-Wittmann S, Falette N, Duriez C, Walden PD, Puisieux A (October 2002). "BTG2(TIS21/PC3) induces neuronal differentiation and prevents apoptosis of terminally differentiated PC12 cells". Oncogene. 21 (44): 6772–78. doi:10.1038/sj.onc.1205888. PMID 12360398.
23. Farioli-Vecchioli S, Saraulli D, Costanzi M, Leonardi L, Cinà I, Micheli L, Nutini M, Longone P, Oh SP, Cestari V, Tirone F (December 2009). "Impaired terminal differentiation of hippocampal granule neurons and defective contextual memory in PC3/Tis21 knockout mice". PLOS ONE. 4 (12): e8339. doi:10.1371/journal.pone.0008339. PMC 2791842. PMID 20020054.
24. Passeri D, Marcucci A, Rizzo G, Billi M, Panigada M, Leonardi L, Tirone F, Grignani F (July 2006). "Btg2 enhances retinoic acid-induced differentiation by modulating histone H4 methylation and acetylation". Molecular and Cellular Biology. 26 (13): 5023–32. doi:10.1128/MCB.01360-05. PMC 1489145. PMID 16782888.
25. Lin WJ, Gary JD, Yang MC, Clarke S, Herschman HR (June 1996). "The mammalian immediate-early TIS21 protein and the leukemia-associated BTG1 protein interact with a protein-arginine N-methyltransferase". The Journal of Biological Chemistry. 271 (25): 15034–44. doi:10.1074/jbc.271.25.15034. PMID 8663146.
26. Micheli L, Ceccarelli M, Farioli-Vecchioli S, Tirone F (December 2015). "Control of the Normal and Pathological Development of Neural Stem and Progenitor Cells by the PC3/Tis21/Btg2 and Btg1 Genes" (PDF). Journal of Cellular Physiology. 230 (12): 2881–90. doi:10.1002/jcp.25038. PMID 25967096.
27. Ceccarelli M, Micheli L, D'Andrea G, De Bardi M, Scheijen B, Ciotti M, Leonardi L, Luvisetto S, Tirone F (December 2015). "Altered cerebellum development and impaired motor coordination in mice lacking the Btg1 gene: Involvement of cyclin D1" (PDF). Developmental Biology. 408 (1): 109–25. doi:10.1016/j.ydbio.2015.10.007. PMID 26524254.
28. Farioli-Vecchioli S, Micheli L, Saraulli D, Ceccarelli M, Cannas S, Scardigli R, Leonardi L, Cinà I, Costanzi M, Ciotti MT, Moreira P, Rouault JP, Cestari V, Tirone F (2012). "Btg1 is Required to Maintain the Pool of Stem and Progenitor Cells of the Dentate Gyrus and Subventricular Zone". Frontiers in Neuroscience. 6: 124. doi:10.3389/fnins.2012.00124. PMC 3431174. PMID 22969701.
29. Tirone F, Farioli-Vecchioli S, Micheli L, Ceccarelli M, Leonardi L (2013). "Genetic control of adult neurogenesis: interplay of differentiation, proliferation and survival modulates new neurons function, and memory circuits". Frontiers in Cellular Neuroscience. 7: 59. doi:10.3389/fncel.2013.00059. PMC 3653098. PMID 23734097.
30. Ceccarelli M, Micheli L, D'Andrea G, De Bardi M, Scheijen B, Ciotti M, Leonardi L, Luvisetto S, Tirone F (December 2015). "Altered cerebellum development and impaired motor coordination in mice lacking the Btg1 gene: Involvement of cyclin D1". Developmental Biology. 408 (1): 109–25. doi:10.1016/j.ydbio.2015.10.007. PMID 26524254.http://www.inmm.cnr.it/tirone/pdfs/Dev%20Biol%202015.pdf
31. Farioli-Vecchioli S, Cinà I, Ceccarelli M, Micheli L, Leonardi L, Ciotti MT, De Bardi M, Di Rocco C, Pallini R, Cavallaro S, Tirone F (October 2012). "Tis21 knock-out enhances the frequency of medulloblastoma in Patched1 heterozygous mice by inhibiting the Cxcl3-dependent migration of cerebellar neurons". The Journal of Neuroscience. 32 (44): 15547–64. doi:10.1523/JNEUROSCI.0412-12.2012. PMC 6621585. PMID 23115191.
32. Ceccarelli M, Micheli L, Tirone F (2016). "Suppression of Medulloblastoma Lesions by Forced Migration of Preneoplastic Precursor Cells with Intracerebellar Administration of the Chemokine Cxcl3". Frontiers in Pharmacology. 7: 484. doi:10.3389/fphar.2016.00484. PMC 5159413. PMID 28018222.
33. Prévôt D, Voeltzel T, Birot AM, Morel AP, Rostan MC, Magaud JP, Corbo L (January 2000). "The leukemia-associated protein Btg1 and the p53-regulated protein Btg2 interact with the homeoprotein Hoxb9 and enhance its transcriptional activation". The Journal of Biological Chemistry. 275 (1): 147–53. doi:10.1074/jbc.275.1.147. PMID 10617598.
34. Berthet C, Guéhenneux F, Revol V, Samarut C, Lukaszewicz A, Dehay C, Dumontet C, Magaud JP, Rouault JP (January 2002). "Interaction of PRMT1 with BTG/TOB proteins in cell signalling: molecular analysis and functional aspects". Genes to Cells. 7 (1): 29–39. doi:10.1046/j.1356-9597.2001.00497.x. PMID 11856371.
35. Prévôt D, Morel AP, Voeltzel T, Rostan MC, Rimokh R, Magaud JP, Corbo L (March 2001). "Relationships of the antiproliferative proteins BTG1 and BTG2 with CAF1, the human homolog of a component of the yeast CCR4 transcriptional complex: involvement in estrogen receptor alpha signaling pathway". The Journal of Biological Chemistry. 276 (13): 9640–8. doi:10.1074/jbc.M008201200. PMID 11136725.
36. Micheli L, D'Andrea G, Leonardi L, Tirone F (2017). "HDAC1, HDAC4, and HDAC9 Bind to PC3/Tis21/Btg2 and Are Required for Its Inhibition of Cell Cycle Progression and Cyclin D1 Expression" (PDF). Journal of Cellular Physiology. 232 (7): 1696–1707. doi:10.1002/jcp.25467. PMID 27333946.

Further reading

• Puisieux A, Magaud JP (April 1999). "[Mechanisms of BTG2 activity, a transcriptional target of p53: evidences and hypothesis]". Bulletin du Cancer. 86 (4): 358–64. PMID 10341341.
• Rouault JP, Prévôt D, Berthet C, Birot AM, Billaud M, Magaud JP, Corbo L (August 1998). "Interaction of BTG1 and p53-regulated BTG2 gene products with mCaf1, the murine homolog of a component of the yeast CCR4 transcriptional regulatory complex". The Journal of Biological Chemistry. 273 (35): 22563–9. doi:10.1074/jbc.273.35.22563. PMID 9712883.
• Walden PD, Lefkowitz GK, Ficazzola M, Gitlin J, Lepor H (November 1998). "Identification of genes associated with stromal hyperplasia and glandular atrophy of the prostate by mRNA differential display". Experimental Cell Research. 245 (1): 19–26. doi:10.1006/excr.1998.4237. PMID 9828097.
• Lin WJ, Chang YF, Wang WL, Huang CY (March 2001). "Mitogen-stimulated TIS21 protein interacts with a protein-kinase-Calpha-binding protein rPICK1". The Biochemical Journal. 354 (Pt 3): 635–43. doi:10.1042/0264-6021:3540635. PMC 1221695. PMID 11237868.
• Yoshida Y, Hosoda E, Nakamura T, Yamamoto T (June 2001). "Association of ANA, a member of the antiproliferative Tob family proteins, with a Caf1 component of the CCR4 transcriptional regulatory complex". Japanese Journal of Cancer Research. 92 (6): 592–6. doi:10.1111/j.1349-7006.2001.tb01135.x. PMC 5926753. PMID 11429045.
• Ficazzola MA, Fraiman M, Gitlin J, Woo K, Melamed J, Rubin MA, Walden PD (August 2001). "Antiproliferative B cell translocation gene 2 protein is down-regulated post-transcriptionally as an early event in prostate carcinogenesis". Carcinogenesis. 22 (8): 1271–9. doi:10.1093/carcin/22.8.1271. PMID 11470758.
• Duriez C, Falette N, Audoynaud C, Moyret-Lalle C, Bensaad K, Courtois S, Wang Q, Soussi T, Puisieux A (January 2002). "The human BTG2/TIS21/PC3 gene: genomic structure, transcriptional regulation and evaluation as a candidate tumor suppressor gene". Gene. 282 (1–2): 207–14. doi:10.1016/S0378-1119(01)00825-3. PMID 11814693.

External links

• Human BTG2 genome location and BTG2 gene details page in the UCSC Genome Browser.
• Overview of all the structural information available in the PDB for UniProt: P78543 (Human Protein BTG2) at the PDBe-KB.
• Overview of all the structural information available in the PDB for UniProt: Q04211 (Mouse Protein BTG2) at the PDBe-KB.