Biology:GLI1

From HandWiki
Short description: Protein-coding gene in humans


A representation of the 3D structure of the protein myoglobin showing turquoise α-helices.
Generic protein structure example

Zinc finger protein GLI1 also known as glioma-associated oncogene is a protein that in humans is encoded by the GLI1 gene. It was originally isolated from human glioblastoma cells.[1]

Function

The Gli proteins are the effectors of Hedgehog (Hh) signaling and have been shown to be involved in cell fate determination, proliferation and patterning in many cell types and most organs during embryo development.[2] In the developing spinal cord the target genes of Gli proteins, that are themselves transcription factors, are arranged into a complex gene regulatory network that translates the extracellular concentration gradient of Sonic hedgehog into different cell fates along the dorsoventral axis.[3]

The Gli transcription factors activate/inhibit transcription by binding to Gli responsive genes and by interacting with the transcription complex. The Gli transcription factors have DNA binding zinc finger domains which bind to consensus sequences on their target genes to initiate or suppress transcription.[4] Yoon[5] showed that mutating the Gli zinc finger domain inhibited the proteins effect proving its role as a transcription factor. Gli proteins have an 18-amino acid region highly similar to the α-helical herpes simplex viral protein 16 activation domain. This domain contains a consensus recognition element for the human TFIID TATA box-binding protein associated factor TAFII31.[5] Other proteins such as Missing in Metastasis (MIM/BEG4) have been shown to potentiate the effects of the Gli transcription factors on target gene transcription. Gli and MIM have been shown to act synergistically to induce epidermal growth and MIM + Gli1 overexpressing grafts show similar growth patterns to Shh grafts.[6]

Gli family

There are three members of the family; Gli1, Gli2 and Gli3 which are all transcription factors mediating the Hh pathway. The GLI1, GLI2, and GLI3 genes encode transcription factors which all contain conserved tandem C2-H2 zinc finger domains and a consensus histidine/cysteine linker sequence between zinc fingers. This Gli motif is related to those of Kruppel which is a Drosophila segmentation gene of the gap class.[7] In transgenic mice, mutant Gli1 lacking the zinc fingers does not induce Sonic Hedgehog (Shh) targets.[8] The conserved stretch of 9 amino acids connects the C-terminal histidine of one finger to the N-terminal cysteine of the next. The GLI consensus finger amino acid sequence is [Y/F]JXCX3GCX3[F/Y]X5LX2HX4H[T/S]GEKP.[7] The Gli1 and Gli2 protein zinc finger DNA binding domain have been shown to bind to the DNA consensus GLI binding site GACCACCCA. [9]

Gli Proteins transcriptional regulation is tissue specific for many targets. For example, Gli1 in primary keratinocytes upregulates FOXM1[10] whereas in mesenchymal C3H10T1/2 cells it has been shown to upregulate platelet-derived growth factor receptor PDGFRa.[11]

Human Gli1 encodes a transcription activator involved in development that is a known oncogene.[5][12] It has been found that N-terminal regions of Gli1 recruit histone deacetylase complexes via SuFu, which are involved in DNA folding in chromosomes.[13] This may negatively regulate transcription indicating Gli1 could act as transcriptional inhibitor as well as an activator.[14] The human GLI1 promoter region is regulated by a 1.4 kb 5’ region including a 5’ flanking sequence, an untranslated exon and 425bp of the first intron. Numerous proteins such as Sp1, USF1, USF2, and Twist are also involved in Gli1 promoter regulation.[15][16][17] During mouse embryo development Gli1 expression can be detected in the gut mesoderm, ventral neural tube, ependymal layer of the spinal cord, forebrain, midbrain, cerebellum, and in sites of endochondral bone formation.[18][19][20] Some of the downstream gene targets of human Gli1 include regulators of the cell cycle and apoptosis such as cyclin D2 and plakoglobin respectively.[21] Gli1 also upregulates FoxM1 in BCC.[10] Gli1 expression can also mimic Shh expression in certain cell types.[22]

Isolation

GLI1 was originally isolated from a glioma tumour and has been found to be up regulated in many tumors including muscle, brain and skin tumors such as Basal cell carcinoma (BCC).[23] DNA copy-number alterations that contribute to increased conversion of the oncogenes Gli1–3 into transcriptional activators by the Hedgehog signaling pathway are included in a genome-wide pattern, which was found to be correlated with an astrocytoma patient’s outcome.[24] Shh and the Gli genes are normally expressed in hair follicles, and skin tumours expressing Gli1 may arise from hair follicles. The level of Gli1 expression correlates with the tumor grade in bone and soft tissue sarcomas.[25] Transgenic mice and frogs overexpressing Gli1 develop BCC like tumours as well as other hair follicle-derived neoplasias, such as trichoepitheliomas, cylindromas, and trichoblastomas.[22][26] Expression of Gli1 in the embryonic frog epidermis results in the development of tumours that express endogenous Gli1. This suggests that overexpressed Gli1 alone is probably sufficient for tumour development[26][27] Mutations leading to the expression of Gli1 in basal cells are thus predicted to induce BCC formation.[22]

Interactions

GLI1 has been shown to interact with:

References

  1. ↑ "Identification of an amplified, highly expressed gene in a human glioma". Science 236 (4797): 70–3. April 1987. doi:10.1126/science.3563490. PMID 3563490. Bibcode: 1987Sci...236...70K. 
  2. ↑ "Gli proteins encode context-dependent positive and negative functions: implications for development and disease.". Development 126 (14): 3205–16. June 1999. doi:10.1242/dev.126.14.3205. PMID 10375510. 
  3. ↑ "Boolean modelling reveals new regulatory connections between transcription factors orchestrating the development of the ventral spinal cord". PLOS ONE 9 (11): 11430. November 2014. doi:10.1371/journal.pone.0111430. PMID 25398016. Bibcode: 2014PLoSO...9k1430L. 
  4. ↑ "A binding site for Gli proteins is essential for HNF-3beta floor plate enhancer activity in transgenics and can respond to Shh in vitro". Development 124 (7): 1313–22. April 1997. doi:10.1242/dev.124.7.1313. PMID 9118802. 
  5. ↑ 5.0 5.1 5.2 "Characterization of the promoter region and genomic organization of GLI, a member of the Sonic hedgehog-Patched signaling pathway". Gene 209 (1–2): 1–11. March 1998. doi:10.1016/S0378-1119(97)00668-9. PMID 9524201. 
  6. ↑ "MIM/BEG4, a Sonic hedgehog-responsive gene that potentiates Gli-dependent transcription". Genes Dev. 18 (22): 2724–9. November 2004. doi:10.1101/gad.1221804. PMID 15545630. 
  7. ↑ 7.0 7.1 "The GLI-Kruppel family of human genes". Mol Cell Biol 8 (8): 3104–13. August 1988. doi:10.1128/mcb.8.8.3104. PMID 2850480. PMC 363537. http://nsuworks.nova.edu/cgi/viewcontent.cgi?article=1137&context=cnso_bio_facarticles. 
  8. ↑ "Mouse Gli1 mutants are viable but have defects in SHH signaling in combination with a Gli2 mutation". Development 127 (8): 1593–605. April 2000. doi:10.1242/dev.127.8.1593. PMID 10725236. 
  9. ↑ "The GLI gene encodes a nuclear protein which binds specific sequences in the human genome.". Mol Cell Biol 10 (2): 634–42. February 1990. doi:10.1128/mcb.10.2.634. PMID 2105456. 
  10. ↑ 10.0 10.1 "FOXM1 is a downstream target of Gli1 in basal cell carcinomas.". Cancer Res. 62 (16): 4773–80. August 2002. PMID 12183437. 
  11. ↑ "A role of PDGFRalpha in basal cell carcinoma proliferation". Proc Natl Acad Sci U S A 98 (16): 9255–9. July 2001. doi:10.1073/pnas.151173398. PMID 11481486. Bibcode: 2001PNAS...98.9255X. 
  12. ↑ "Identification of an amplified, highly expressed gene in a human glioma.". Science 236 (4797): 70–3. April 1987. doi:10.1126/science.3563490. PMID 3563490. Bibcode: 1987Sci...236...70K. 
  13. ↑ "Suppressor of Fused represses Gli-mediated transcription by recruiting the SAP18-mSin3 corepressor complex.". Proc Natl Acad Sci U S A 99 (8): 5442–7. April 2002. doi:10.1073/pnas.082096999. PMID 11960000. Bibcode: 2002PNAS...99.5442C. 
  14. ↑ "Gli proteins and the control of spinal-cord patterning". EMBO Rep. 4 (8): 761–5. August 2003. doi:10.1038/sj.embor.embor896. PMID 12897799. 
  15. ↑ "Cooperative E-box regulation of human GLI1 by TWIST and USF.". Genesis 32 (4): 247–58. April 2002. doi:10.1002/gene.10078. PMID 11948912. 
  16. ↑ "Twist protein in mouse embryogenesis.". Dev. Biol. 189 (2): 205–14. September 1997. doi:10.1006/dbio.1997.8614. PMID 9299114. 
  17. ↑ "Repression of muscle-specific gene activation by the murine Twist protein.". Exp. Cell Res. 232 (2): 295–303. May 1997. doi:10.1006/excr.1997.3541. PMID 9168805. 
  18. ↑ "Expression of three mouse homologs of the Drosophila segment polarity gene cubitus interruptus, Gli, Gli-2, and Gli-3, in ectoderm- and mesoderm-derived tissues suggests multiple roles during postimplantation development". Dev. Biol. 162 (2): 402–13. 1994. doi:10.1006/dbio.1994.1097. PMID 8150204. 
  19. ↑ "gli, a zinc finger transcription factor and oncogene, is expressed during normal mouse development". Dev. Dyn. 196 (2): 91–102. 1993. doi:10.1002/aja.1001960203. PMID 8364225. 
  20. ↑ "Purkinje-cell-derived Sonic hedgehog regulates granule neuron precursor cell proliferation in the developing mouse cerebellum". Curr. Biol. 9 (8): 445–8. 1999. doi:10.1016/s0960-9822(99)80195-x. PMID 10226030. 
  21. ↑ "Gene expression profiling leads to identification of GLI1-binding elements in target genes and a role for multiple downstream pathways in GLI1-induced cell transformation". J. Biol. Chem. 277 (7): 5548–55. February 2002. doi:10.1074/jbc.M105708200. PMID 11719506. 
  22. ↑ 22.0 22.1 22.2 "Activation of the transcription factor Gli1 and the Sonic hedgehog signalling pathway in skin tumours". Nature 389 (6653): 876–81. 1997. doi:10.1038/39918. PMID 9349822. Bibcode: 1997Natur.389..876D. 
  23. ↑ "Hedgehog signaling and the Gli code in stem cells, cancer, and metastases". Sci Signal 4 (200): pt9. 2011. doi:10.1126/scisignal.2002540. PMID 22114144. 
  24. ↑ "Platform-Independent Genome-Wide Pattern of DNA Copy-Number Alterations Predicting Astrocytoma Survival and Response to Treatment Revealed by the GSVD Formulated as a Comparative Spectral Decomposition". PLOS ONE 11 (10): e0164546. October 2016. doi:10.1371/journal.pone.0164546. PMID 27798635. Bibcode: 2016PLoSO..1164546A. 
  25. ↑ "Activation of the transcription factor Gli1 and the Sonic hedgehog signalling pathway in skin tumours.". Nature 389 (6653): 876–81. October 1997. doi:10.1038/39918. PMID 9349822. Bibcode: 1997Natur.389..876D. "Erratum in: Nature 1997 December 4;390(6659):536.". 
  26. ↑ 26.0 26.1 "Induction of basal cell carcinomas and trichoepitheliomas in mice overexpressing GLI-1". Proc. Natl. Acad. Sci. U.S.A. 97 (7): 3438–43. 2000. doi:10.1073/pnas.050467397. PMID 10725363. 
  27. ↑ "Gli1 Regulates S-phase Checkpoint in Tumor Cells via Bid and its Inhibition Sensitizes to DNA Topoisomerase 1 Inhibitors.". Journal of Biological Chemistry 289 (45): 31513–25. 2014. doi:10.1074/jbc.M114.606483. PMID 25253693. 
  28. ↑ "Suppressor of Fused represses Gli-mediated transcription by recruiting the SAP18-mSin3 corepressor complex". Proc. Natl. Acad. Sci. U.S.A. 99 (8): 5442–7. April 2002. doi:10.1073/pnas.082096999. PMID 11960000. Bibcode: 2002PNAS...99.5442C. 
  29. ↑ "Gli regulation by the opposing activities of fused and suppressor of fused". Nat. Cell Biol. 2 (5): 310–2. May 2000. doi:10.1038/35010610. PMID 10806483. 
  30. ↑ "Characterization of the human suppressor of fused, a negative regulator of the zinc-finger transcription factor Gli". J. Cell Sci. 112 (23): 4437–48. December 1999. doi:10.1242/jcs.112.23.4437. PMID 10564661. 
  31. ↑ "Mammalian suppressor-of-fused modulates nuclear-cytoplasmic shuttling of Gli-1". Nat. Cell Biol. 1 (5): 312–9. September 1999. doi:10.1038/13031. PMID 10559945. 
  32. ↑ "Characterization of the physical interaction of Gli proteins with SUFU proteins". J. Biol. Chem. 278 (7): 5116–22. February 2003. doi:10.1074/jbc.M209492200. PMID 12426310. 
  33. ↑ "Physical and functional interactions between Zic and Gli proteins". J. Biol. Chem. 276 (10): 6889–92. March 2001. doi:10.1074/jbc.C000773200. PMID 11238441. 

External links



Retrieved from "https://handwiki.org/wiki/index.php?title=Biology:GLI1&oldid=3638590"