Development of neural and sensory primordia at the early stages of embryogenesis depends on the activity of two B1 Sox transcription factors, Sox2 and Sox3. The embryonic expression patterns of the Sox2 and Sox3 genes are similar, yet they show gene-unique features. We screened for enhancers of the 231-kb genomic region encompassing Sox3 of chicken, and identified 13 new enhancers that showed activity in different domains of the neuro-sensory primordia. Combined with the three Sox3-proximal enhancers determined previously, at least 16 enhancers were involved in Sox3 regulation. Starting from the NP1 enhancer, more enhancers with different specificities are activated in sequence, resulting in complex overlapping patterns of enhancer activities. NP1 was activated in the caudal lateral epiblast adjacent to the posterior growing end of neural plate, and by the combined action of Wnt and Fgf signaling, similar to the Sox2 N1 enhancer involved in neural/mesodermal dichotomous cell lineage segregation. The Sox3 D5 enhancer and Sox2 N3 enhancer were also activated similarly in the diencephalon, optic vesicle and lens placode, suggesting analogies in their regulation. In general, however, the specificities of the enhancers were not identical between Sox3 and Sox2, including the cases of the NP1 and D5 enhancers.
References
[1]
Kamachi, Y.; Uchikawa, M.; Collignon, J.; Lovell-Badge, R.; Kondoh, H. Involvement of Sox1, 2 and 3 in the early and subsequent molecular events of lens induction. Development 1998, 125, 2521–2532.
[2]
Tanaka, S.; Kamachi, Y.; Tanouchi, A.; Hamada, H.; Jing, N.; Kondoh, H. Interplay of SOX and POU factors in regulation of the Nestin gene in neural primordial cells. Mol. Cell Biol. 2004, 24, 8834–8846.
[3]
Inoue, M.; Kamachi, Y.; Matsunami, H.; Imada, K.; Uchikawa, M.; Kondoh, H. PAX6 and SOX2-dependent regulation of the Sox2 enhancer N-3 involved in embryonic visual system development. Genes Cells 2007, 12, 1049–1061, doi:10.1111/j.1365-2443.2007.01114.x.
[4]
Kamachi, Y.; Iwafuchi, M.; Okuda, Y.; Takemoto, T.; Uchikawa, M.; Kondoh, H. Evolution of non-coding regulatory sequences involved in the developmental process: reflection of differential employment of paralogous genes as highlighted by Sox2 and group B1 Sox genes. Proc. Jpn. Acad. Ser. B Phys. Biol. Sci. 2009, 85, 55–68, doi:10.2183/pjab.85.55.
[5]
Uchikawa, M.; Yoshida, M.; Iwafuchi-Doi, M.; Matsuda, K.; Ishida, Y.; Takemoto, T.; Kondoh, H. B1 and B2 Sox gene expression during neural plate development in chicken and mouse embryos: Universal versus species-dependent features. Dev. Growth Differ. 2011, 53, 761–771, doi:10.1111/j.1440-169X.2011.01286.x.
[6]
Collignon, J.; Sockanathan, S.; Hacker, A.; Cohen-Tannoudji, M.; Norris, D.; Rastan, S.; Stevanovic, M.; Goodfellow, P.N.; Lovell-Badge, R. A comparison of the properties of Sox-3 with Sry and two related genes, Sox-1 and Sox-2. Development 1996, 122, 509–520.
[7]
Wood, H.B.; Episkopou, V. Comparative expression of the mouse Sox1, Sox2 and Sox3 genes from pre-gastrulation to early somite stages. Mech. Dev. 1999, 86, 197–201.
[8]
Okuda, Y.; Yoda, H.; Uchikawa, M.; Furutani-Seiki, M.; Takeda, H.; Kondoh, H.; Kamachi, Y. Comparative genomic and expression analysis of group B1 sox genes in zebrafish indicates their diversification during vertebrate evolution. Dev. Dyn. 2006, 235, 811–825, doi:10.1002/dvdy.20678.
[9]
Penzel, R.; Oschwald, R.; Chen, Y.; Tacke, L.; Grunz, H. Characterization and early embryonic expression of a neural specific transcription factor xSOX3 in Xenopus laevis. Int. J. Dev. Biol. 1997, 41, 667–477.
[10]
Rex, M.; Orme, A.; Uwanogho, D.; Tointon, K.; Wigmore, P.M.; Sharpe, P.T.; Scotting, P.J. Dynamic expression of chicken Sox2 and Sox3 genes in ectoderm induced to form neural tissue. Dev. Dyn. 1997, 209, 323–232, doi:10.1002/(SICI)1097-0177(199707)209:3<323::AID-AJA7>3.0.CO;2-K.
[11]
Uwanogho, D.; Rex, M.; Cartwright, E.J.; Pearl, G.; Healy, C.; Scotting, P.J.; Sharpe, P.T. Embryonic expression of the chicken Sox2, Sox3 and Sox11 genes suggests an interactive role in neuronal development. Mech. Dev. 1995, 49, 23–36, doi:10.1016/0925-4773(94)00299-3.
[12]
Rogers, C.D.; Archer, T.C.; Cunningham, D.D.; Grammer, T.C.; Casey, E.M. Sox3 expression is maintained by FGF signaling and restricted to the neural plate by Vent proteins in the Xenopus embryo. Dev. Biol. 2008, 313, 307–319, doi:10.1016/j.ydbio.2007.10.023.
[13]
Schlosser, G.; Ahrens, K. Molecular anatomy of placode development in Xenopus laevis. Dev. Biol. 2004, 271, 439–466, doi:10.1016/j.ydbio.2004.04.013.
[14]
Uchikawa, M.; Kamachi, Y.; Kondoh, H. Two distinct subgroups of Group B Sox genes for transcriptional activators and repressors: Their expression during embryonic organogenesis of the chicken. Mech. Dev. 1999, 84, 103–120.
[15]
Nitta, K.R.; Takahashi, S.; Haramoto, Y.; Fukuda, M.; Onuma, Y.; Asashima, M. Expression of Sox1 during Xenopus early embryogenesis. Biochem. Biophys. Res. Commun. 2006, 351, 287–293, doi:10.1016/j.bbrc.2006.10.040.
[16]
Okuda, Y.; Ogura, E.; Kondoh, H.; Kamachi, Y. B1 SOX coordinate cell specification with patterning and morphogenesis in the early zebrafish embryo. PLoS Genet. 2010, 6, doi:10.1371/journal.pgen.1000936.
[17]
Rizzoti, K.; Lovell-Badge, R. SOX3 activity during pharyngeal segmentation is required for craniofacial morphogenesis. Development 2007, 134, 3437–3448.
[18]
Iwafuchi-Doi, M.; Yoshida, Y.; Onichtchouk, D.; Leichsenring, M.; Driever, W.; Takemoto, T.; Uchikawa, M.; Kamachi, Y.; Kondoh, H. The Pou5f1/Pou3f-dependent but SoxB-independent regulation of conserved enhancer N2 initiates Sox2 expression during epiblast to neural plate stages in vertebrates. Dev. Biol. 2011, 352, 354–366, doi:10.1016/j.ydbio.2010.12.027.
[19]
Nishiguchi, S.; Wood, H.; Kondoh, H.; Lovell-Badge, R.; Episkopou, V. Sox1 directly regulates the gamma-crystallin genes and is essential for lens development in mice. Genes Dev. 1998, 12, 776–781.
[20]
Ekonomou, A.; Kazanis, I.; Malas, S.; Wood, H.; Alifragis, P.; Denaxa, M.; Karagogeos, D.; Constanti, A.; Lovell-Badge, R.; Episkopou, V. Neuronal migration and ventral subtype identity in the telencephalon depend on SOX1. PLoS Biol. 2005, 3, doi:10.1371/journal.pbio.0030186.
[21]
Avilion, A.A.; Nicolis, S.K.; Pevny, L.H.; Perez, L.; Vivian, N.; Lovell-Badge, R. Multipotent cell lineages in early mouse development depend on SOX2 function. Genes Dev. 2003, 17, 126–140, doi:10.1101/gad.224503.
[22]
Rizzoti, K.; Brunelli, S.; Carmignac, D.; Thomas, P.Q.; Robinson, I.C.; Lovell-Badge, R. SOX3 is required during the formation of the hypothalamo-pituitary axis. Nat. Genet. 2004, 36, 247–255, doi:10.1038/ng1309.
[23]
Weiss, J.; Meeks, J.J.; Hurley, L.; Raverot, G.; Frassetto, A.; Jameson, J.L. Sox3 is required for gonadal function, but not sex determination, in males and females. Mol. Cell Biol. 2003, 23, 8084–8891, doi:10.1128/MCB.23.22.8084-8091.2003.
[24]
Graham, V.; Khudyakov, J.; Ellis, P.; Pevny, L. SOX2 functions to maintain neural progenitor identity. Neuron 2003, 39, 749–765.
[25]
Pevny, L.H.; Nicolis, S.K. Sox2 roles in neural stem cells. Int. J. Biochem. Cell Biol. 2010, 42, 421–424, doi:10.1016/j.biocel.2009.08.018.
[26]
Dee, C.T.; Hirst, C.S.; Shih, Y.H.; Tripathi, V.B.; Patient, R.K.; Scotting, P.J. Sox3 regulates both neural fate and differentiation in the zebrafish ectoderm. Dev. Biol. 2008, 320, 289–301, doi:10.1016/j.ydbio.2008.05.542.
[27]
Uchikawa, M.; Ishida, Y.; Takemoto, T.; Kamachi, Y.; Kondoh, H. Functional analysis of chicken Sox2 enhancers highlights an array of diverse regulatory elements that are conserved in mammals. Dev. Cell 2003, 4, 509–519, doi:10.1016/S1534-5807(03)00088-1.
[28]
Okamoto, R.; Uchikawa, M.; Kondoh, H. Twenty-seven enhancers and additional enhancer candidates for Sox2 regulation are distributed within a 200 kb region of the chicken genome. Nucleic Acids Res. 2012.
[29]
Takemoto, T.; Uchikawa, M.; Kamachi, Y.; Kondoh, H. Convergence of Wnt and FGF signals in the genesis of posterior neural plate through activation of the Sox2 enhancer N-1. Development 2006, 133, 297–306.
[30]
Saigou, Y.; Kamimura, Y.; Inoue, M.; Kondoh, H.; Uchikawa, M. Regulation of Sox2 in the pre-placodal cephalic ectoderm and central nervous system by enhancer N-4. Dev. Growth Differ. 2010, 52, 397–408.
[31]
Iwafuchi-Doi, M.; Matsuda, K.; Murakami, K.; Niwa, H.; Tesar, P.; Aruga, J.; Matsuo, I.; Kondoh, H. Transcriptional regulatory networks in epiblast cells and during anterior neural plate development as modeled in epiblast stem cells. Development 2012, 139, 3926–3937, doi:10.1242/dev.085936.
[32]
Kondoh, H.; Takemoto, T. Axial stem cells deriving both posterior neural and mesodermal tissues during gastrulation. Curr. Opin. Genet. Dev. 2012, 22, 374–380, doi:10.1016/j.gde.2012.03.006.
[33]
Takemoto, T.; Uchikawa, M.; Yoshida, M.; Bell, D.M.; Lovell-Badge, R.; Papaioannou, V.E.; Kondoh, H. Tbx6-dependent Sox2 regulation determines neural or mesodermal fate in axial stem cells. Nature 2011, 470, 394–398, doi:10.1038/nature09729.
[34]
van Rooijen, C.; Simmini, S.; Bialecka, M.; Neijts, R.; van de Ven, C.; Beck, F.; Deschamps, J. Evolutionarily conserved requirement of Cdx for post-occipital tissue emergence. Development 2012, 139, 2576–2583, doi:10.1242/dev.079848.
[35]
Brunelli, S.; Silva Casey, E.; Bell, D.; Harland, R.; Lovell-Badge, R. Expression of Sox3 throughout the developing central nervous system is dependent on the combined action of discrete, evolutionarily conserved regulatory elements. Genesis 2003, 36, 12–24, doi:10.1002/gene.10193.
[36]
Kondoh, H.; Uchikawa, M. Dissection of chick genomic regulatory regions. Meth. Cell Biol. 2008, 87, 313–336.
[37]
Kovacevic Grujicic, N.; Mojsin, M.; Krstic, A.; Stevanovic, M. Functional characterization of the human SOX3 promoter: identification of transcription factors implicated in basal promoter activity. Gene 2005, 344, 287–297, doi:10.1016/j.gene.2004.11.006.
[38]
Krstic, A.; Mojsin, M.; Stevanovic, M. Regulation of SOX3 gene expression is driven by multiple NF-Y binding elements. Arch. Biochem. Biophys. 2007, 467, 163–173, doi:10.1016/j.abb.2007.08.029.
[39]
Mojsin, M.; Stevanovic, M. PBX1 and MEIS1 up-regulate SOX3 gene expression by direct interaction with a consensus binding site within the basal promoter region. Biochem. J. 2009, 425, 107–116.
[40]
Sawicki, J.A.; Morris, R.J.; Monks, B.; Sakai, K.; Miyazaki, J. A composite CMV-IE enhancer/beta-actin promoter is ubiquitously expressed in mouse cutaneous epithelium. Exp. Cell Res. 1998, 244, 367–369, doi:10.1006/excr.1998.4175.
