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Foxn1 regulates key target genes essential for T cell development in postnatal thymic epithelial cells

Abstract

Thymic epithelial cell differentiation, growth and function depend on the expression of the transcription factor Foxn1; however, its target genes have never been physically identified. Using static and inducible genetic model systems and chromatin studies, we developed a genome-wide map of direct Foxn1 target genes for postnatal thymic epithelia and defined the Foxn1 binding motif. We determined the function of Foxn1 in these cells and found that, in addition to the transcriptional control of genes involved in the attraction and lineage commitment of T cell precursors, Foxn1 regulates the expression of genes involved in antigen processing and thymocyte selection. Thus, critical events in thymic lympho-stromal cross-talk and T cell selection are indispensably choreographed by Foxn1.

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Figure 1: Transgenic rescue of nude phenotype in Foxn1wt*/wt* mice expressing a chimeric Foxn1-Flag protein.
Figure 2: Foxn1 availability in TECs determines T cell developmental defects.
Figure 3: Foxn1 ChIP-seq analysis.
Figure 4: Intersection of Foxn1 ChIP-seq and RNA-seq analyses.
Figure 5: Psmb11 and Cd83 are direct targets of Foxn1.
Figure 6: Comparative analysis of the effect of a loss of Cd83 expression and expression of a hypomorphic Foxn1 allele, respectively, on intrathymic T cell development.

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References

  1. Anderson, G. & Takahama, Y. Thymic epithelial cells: working class heroes for T cell development and repertoire selection. Trends Immunol. 33, 256–263 (2012).

    CAS  PubMed  Google Scholar 

  2. Holländer, G. et al. Cellular and molecular events during early thymus development. Immunol. Rev. 209, 28–46 (2006).

    PubMed  Google Scholar 

  3. Klein, L., Kyewski, B., Allen, P.M. & Hogquist, K.A. Positive and negative selection of the T cell repertoire: what thymocytes see (and don't see). Nat. Rev. Immunol. 14, 377–391 (2014).

    CAS  PubMed  PubMed Central  Google Scholar 

  4. Stritesky, G.L. et al. Murine thymic selection quantified using a unique method to capture deleted T cells. Proc. Natl. Acad. Sci. USA 110, 4679–4684 (2013).

    CAS  PubMed  PubMed Central  Google Scholar 

  5. Nehls, M., Pfeifer, D., Schorpp, M., Hedrich, H. & Boehm, T. New member of the winged-helix protein family disrupted in mouse and rat nude mutations. Nature 372, 103–107 (1994).

    CAS  PubMed  Google Scholar 

  6. Nehls, M. et al. Two genetically separable steps in the differentiation of thymic epithelium. Science 272, 886–889 (1996).

    CAS  PubMed  Google Scholar 

  7. Bleul, C.C. et al. Formation of a functional thymus initiated by a postnatal epithelial progenitor cell. Nature 441, 992–996 (2006).

    CAS  PubMed  Google Scholar 

  8. Cheng, L. et al. Postnatal tissue-specific disruption of transcription factor FoxN1 triggers acute thymic atrophy. J. Biol. Chem. 285, 5836–5847 (2010).

    CAS  PubMed  Google Scholar 

  9. Nowell, C.S. et al. Foxn1 regulates lineage progression in cortical and medullary thymic epithelial cells but is dispensable for medullary sublineage divergence. PLoS Genet. 7, e1002348 (2011).

    CAS  PubMed  PubMed Central  Google Scholar 

  10. Chen, L., Xiao, S. & Manley, N.R. Foxn1 is required to maintain the postnatal thymic microenvironment in a dosage-sensitive manner. Blood 113, 567–574 (2009).

    CAS  PubMed  PubMed Central  Google Scholar 

  11. Zuklys, S. et al. Stabilized β-catenin in thymic epithelial cells blocks thymus development and function. J. Immunol. 182, 2997–3007 (2009).

    CAS  PubMed  Google Scholar 

  12. Zlotoff, D.A. et al. CCR7 and CCR9 together recruit hematopoietic progenitors to the adult thymus. Blood 115, 1897–1905 (2010).

    CAS  PubMed  PubMed Central  Google Scholar 

  13. Ueno, T. et al. CCR7 signals are essential for cortex-medulla migration of developing thymocytes. J. Exp. Med. 200, 493–505 (2004).

    CAS  PubMed  PubMed Central  Google Scholar 

  14. Daley, S.R., Hu, D.Y. & Goodnow, C.C. Helios marks strongly autoreactive CD4+ T cells in two major waves of thymic deletion distinguished by induction of PD-1 or NF-κB. J. Exp. Med. 210, 269–285 (2013).

    CAS  PubMed  PubMed Central  Google Scholar 

  15. Sansom, S.N. et al. Population and single-cell genomics reveal the Aire dependency, relief from Polycomb silencing, and distribution of self-antigen expression in thymic epithelia. Genome Res. 24, 1918–1931 (2014).

    CAS  PubMed  PubMed Central  Google Scholar 

  16. Schlake, T., Schorpp, M., Nehls, M. & Boehm, T. The nude gene encodes a sequence-specific DNA binding protein with homologs in organisms that lack an anticipatory immune system. Proc. Natl. Acad. Sci. USA 94, 3842–3847 (1997).

    CAS  PubMed  PubMed Central  Google Scholar 

  17. Ara, T. et al. A role of CXC chemokine ligand 12/stromal cell-derived factor-1/pre-B cell growth stimulating factor and its receptor CXCR4 in fetal and adult T cell development in vivo. J. Immunol. 170, 4649–4655 (2003).

    CAS  PubMed  Google Scholar 

  18. Hozumi, K. et al. Delta-like 4 is indispensable in thymic environment specific for T cell development. J. Exp. Med. 205, 2507–2513 (2008).

    CAS  PubMed  PubMed Central  Google Scholar 

  19. Wang, S. et al. Target analysis by integration of transcriptome and ChIP-seq data with BETA. Nat. Protoc. 8, 2502–2515 (2013).

    CAS  PubMed  PubMed Central  Google Scholar 

  20. Langfelder, P. & Horvath, S. WGCNA: an R package for weighted correlation network analysis. BMC Bioinformatics 9, 559 (2008).

    PubMed  PubMed Central  Google Scholar 

  21. Ki, S. et al. Global transcriptional profiling reveals distinct functions of thymic stromal subsets and age-related changes during thymic involution. Cell Rep. 9, 402–415 (2014).

    CAS  PubMed  PubMed Central  Google Scholar 

  22. Dennis, G. Jr. et al. DAVID: Database for annotation, visualization, and integrated discovery. Genome Biol. 4, 3 (2003).

    Google Scholar 

  23. Gommeaux, J. et al. Thymus-specific serine protease regulates positive selection of a subset of CD4+ thymocytes. Eur. J. Immunol. 39, 956–964 (2009).

    CAS  PubMed  Google Scholar 

  24. Zambelli, F., Pesole, G. & Pavesi, G. PscanChIP: finding over-represented transcription factor-binding site motifs and their correlations in sequences from ChIP-Seq experiments. Nucleic Acids Res. 41, W535–43 (2013).

    PubMed  PubMed Central  Google Scholar 

  25. Impey, S. et al. Defining the CREB regulon: a genome-wide analysis of transcription factor regulatory regions. Cell 119, 1041–1054 (2004).

    CAS  PubMed  Google Scholar 

  26. Burnley, P. et al. Role of the p63-FoxN1 regulatory axis in thymic epithelial cell homeostasis during aging. Cell Death Dis. 4, e932 (2013).

    CAS  PubMed  PubMed Central  Google Scholar 

  27. Della Gatta, G. et al. Direct targets of the TRP63 transcription factor revealed by a combination of gene expression profiling and reverse engineering. Genome Res. 18, 939–948 (2008).

    CAS  PubMed  PubMed Central  Google Scholar 

  28. Ripen, A.M., Nitta, T., Murata, S., Tanaka, K. & Takahama, Y. Ontogeny of thymic cortical epithelial cells expressing the thymoproteasome subunit β5t. Eur. J. Immunol. 41, 1278–1287 (2011).

    CAS  PubMed  Google Scholar 

  29. Murata, S. et al. Regulation of CD8+ T cell development by thymus-specific proteasomes. Science 316, 1349–1353 (2007).

    CAS  PubMed  Google Scholar 

  30. Fujimoto, Y. et al. CD83 expression influences CD4+ T cell development in the thymus. Cell 108, 755–767 (2002).

    CAS  PubMed  Google Scholar 

  31. Saini, M. et al. Regulation of Zap70 expression during thymocyte development enables temporal separation of CD4 and CD8 repertoire selection at different signaling thresholds. Sci. Signal. 3, ra23 (2010).

    PubMed  Google Scholar 

  32. Nakagawa, S., Gisselbrecht, S.S., Rogers, J.M., Hartl, D.L. & Bulyk, M.L. DNA-binding specificity changes in the evolution of forkhead transcription factors. Proc. Natl. Acad. Sci. USA 110, 12349–12354 (2013).

    CAS  PubMed  PubMed Central  Google Scholar 

  33. Carroll, J.S. et al. Chromosome-wide mapping of estrogen receptor binding reveals long-range regulation requiring the forkhead protein FoxA1. Cell 122, 33–43 (2005).

    CAS  PubMed  Google Scholar 

  34. Senoo, M., Pinto, F., Crum, C.P. & McKeon, F. p63 Is essential for the proliferative potential of stem cells in stratified epithelia. Cell 129, 523–536 (2007).

    CAS  PubMed  Google Scholar 

  35. Liu, B. et al. Cbx4 regulates the proliferation of thymic epithelial cells and thymus function. Development 140, 780–788 (2013).

    CAS  PubMed  PubMed Central  Google Scholar 

  36. Flomerfelt, F.A. et al. Tbata modulates thymic stromal cell proliferation and thymus function. J. Exp. Med. 207, 2521–2532 (2010).

    CAS  PubMed  PubMed Central  Google Scholar 

  37. Bredenkamp, N., Nowell, C.S. & Blackburn, C.C. Regeneration of the aged thymus by a single transcription factor. Development 141, 1627–1637 (2014).

    CAS  PubMed  PubMed Central  Google Scholar 

  38. Calderón, L. & Boehm, T. Synergistic, context-dependent and hierarchical functions of epithelial components in thymic microenvironments. Cell 149, 159–172 (2012).

    PubMed  Google Scholar 

  39. Rode, I. et al. Foxn1 protein expression in the developing, aging, and regenerating thymus. J. Immunol. 195, 5678–5687 (2015).

    CAS  PubMed  Google Scholar 

  40. Mayer, C.E. et al. Dynamic spatio-temporal contribution of single β5t+ cortical epithelial precursors to the thymus medulla. Eur. J. Immunol. 46, 846–856 (2016).

    CAS  PubMed  PubMed Central  Google Scholar 

  41. Vokes, S.A. et al. Genomic characterization of Gli-activator targets in sonic hedgehog-mediated neural patterning. Development 134, 1977–1989 (2007).

    CAS  PubMed  Google Scholar 

  42. Li, H. & Durbin, R. Fast and accurate short read alignment with Burrows-Wheeler transform. Bioinformatics 25, 1754–1760 (2009).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  43. Lunter, G. & Goodson, M. Stampy: a statistical algorithm for sensitive and fast mapping of Illumina sequence reads. Genome Res. 21, 936–939 (2011).

    CAS  PubMed  PubMed Central  Google Scholar 

  44. Zhang, Y. et al. Model-based analysis of ChIP-Seq (MACS). Genome Biol. 9, R137 (2008).

    PubMed  PubMed Central  Google Scholar 

  45. Robinson, M.D., McCarthy, D.J. & Smyth, G.K. edgeR: a Bioconductor package for differential expression analysis of digital gene expression data. Bioinformatics 26, 139–140 (2010).

    CAS  PubMed  Google Scholar 

  46. Buenrostro, J.D., Wu, B., Chang, H.Y. & Greenleaf, W.J. ATAC-seq: a method for assaying chromatin accessibility genome-wide. Curr. Protoc. Mol. Biol. 2015, 21.29.1–21.29.9 (2015).

    Google Scholar 

Download references

Acknowledgements

We thank E. Christen, R. Recinos, A. Offinger, D. Nebenius-Oosthulzen and A. Klewe-Nebenius for technical support, M. Gaio and S. Harris for secretarial assistance, and J. Lopez-Rios and M. Osterwalder for help establishing ChIP and provision of plasmids. Supported by the Swiss National Foundation (3100- 68310.02 and 3100-122558 to G.A.H.), The Wellcome Trust (105045/Z/14/Z to G.A.H. and C.P.P.; 100643/Z/12/Z to A.H.) the MRC (C.P.P.) and the European Commission within the Seventh Framework Programme (FP7 project 261387 to G.H.).

Author information

Authors and Affiliations

Authors

Contributions

S. Žuklys, S. Zhanybekova, A.H. and G.A.H. designed the experiments. S. Žuklys, C.E.M., S. Zhanybekova, F.G., H.Y.T., K.H., S.M. and M.K. performed the experiments. S. Žuklys, A.H., S. Zhanybekova, F.G., C.E.M., T.B., G.G., C.P.P. and G.A.H. analyzed and/or interpreted the results. G.A.H. wrote the manuscript with contributions from A.H. and S. Žuklys.

Corresponding authors

Correspondence to Saulius Žuklys or Georg A Holländer.

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The authors declare no competing financial interests.

Integrated supplementary information

Supplementary Figure 1 Transgenic expression of a Foxn1-3xFlag fusion protein in Foxn1nu/nu mice.

(a) Schematic display of the targeting strategy to achieve homologous recombination of a bacterial artificial chromosome (BAC) to place in exon 2 of the Foxn1 locus a cDNA encoding a Foxn1 fused at its C-terminus to three Flag sequences, designated Foxn1-Flag. FRT: Flipase recombinase target. (b) Western blot (WB) analysis of total thymus tissue lysates and anti-Flag (a-Flag) immunoprecipitates of thymus tissue lysates of both wild type and Foxn1wt*/wt* mice developed using anti-Flag antibodies. (c) Macroscopic analysis of thymic lobes from 4-5 week old mice of the indicated genotype. (d) Hair growth was restored in Foxn1nu/nu mice either heterozygous (designated Foxn1wt*/-) or homozygous (Foxn1wt*/wt*) for the BAC transgene encoding the Foxn1-Flag fusion protein. (e) Gating strategy used in flow cytometric analysis of TEC subpopulations. (f) cTEC and mTEC cellularity in Foxn1+/+, Foxn1wt*/wt* and Foxn1wt*/- mice. The cellularity was calculated based on flow cytometric data presented in Fig. 1e. *p<0.05. (Student’s t-test). Data is representative of two (b-f) independent experiments (mean ±SD) with sample sizes of three (f). Contour plots (e) are representative and the numbers shown in individual gates represent relative frequencies observed in a representative experiment.

Supplementary Figure 2 Foxn1wt*/– mice demonstrate defects in T cell development and increased frequencies of thymic B cells.

Flow cytometric analysis of 5 week old mice with indicated genotype for (a) CD19 and IgM expression on CD4-CD8- thymocytes; (b) CD4 and CD8 expression on thymocytes at sequential developmental stages as defined by the cell surface expression of CD69 and TCR; (c) Foxp3 and CD25 expression CD4+CD8-TCR+CD5+ thymocytes. *p<0.05. (Student’s t-test (a,b)). Data are representative of two (a-c) independent experiments (mean ±SD) with sample sizes of four. Contour plots (a,b) are representative of data in bar graphs. Numbers shown in individual gates and quadrants of flow cytometry plots represent the frequencies observed in a individual experiment.

Supplementary Figure 3 Foxn1 DNA-binding analysis by ChIP.

(a) ChIP of DNA from two mixed samples (thymoycte:TEC = 5:1, designated TEC +Thymocytes) or sorted thymocytes immunoprecipitated with anti-Flag antibodies (IP) and analyzed by qPCR for enrichment of promoter regions of the FoxN1 candidate genes Psmb11 and Dll4, and Foxp3, as control. (b) Genomic context of Foxn1 ChIP-seq peaks. Enrichment for mm10 RefSeq metagene features and mTEC H3K4me3 ChIP-seq peaks (IDR < 0.01). De novo motif analysis. (c) MEMEChIP-derived Foxn1 binding site motif for all peaks (IDR<0.05; E-value < 10-129). (d) Motif coverage relative to the summit of Foxn1 ChIP-seq peaks for all peaks.

Supplementary Figure 4 RNA-seq differential gene-expression analysis.

Volcano plots of (a) cTEC from Foxn1wt*/- vs. Foxn1wt*/wt* mice, (b) mTEC from Foxn1wt*/- vs. Foxn1wt*/wt* mice, (c) cTEC from iFoxn1Δ7,8 mice vs iFoxn1Δ7,8 mice that lack the Cre-recombinase. Positive fold changes indicate genes with increased expression in the presence of increased transcripts encoding functional Foxn1.

Supplementary Figure 5 Inducible deletion of Foxn1 in cTECs.

(a) Diagram of the targeting strategy to generate mice (designated iFoxn1Δ7,8) with a conditional Foxn1 allele that allows for the deletion of its exons 7 and 8. Germ-line transmitting knock-in mice were crossed to Flp recombinase transgenic mice to remove the PGK-neo cassette. (b) PCR-based analysis of genomic DNA from wild type mice (wt/wt) and mice with either one (wt/lox) or two (lox/lox) targeted alleles using the primers a and b depicted in the panel (a). (c) Strategy to achieve a cTEC-targeted, Dox-inducible deletion of exons 7 and 8 of Foxn1 in these triple-transgenic mice. rtTA is expressed under the transcriptional control of the Psmb11 locus, and TetO is expressed under a minimal CMV promoter.

Supplementary Figure 6 Foxn1 is indispensable for postnatal cTEC function.

(a) Immunofluorescence analysis of thymus tissue from 1 week old iFoxn1Δ7,8 mice injected i.p. with a single dose of Doxycycline (Dox+) or saline (Dox-) and analysed 3 days later. Tissue sections were stained for the expression of Foxn1 (red) and cytokeratin 8 (CK8, a cortical TEC marker; green). Scale bar 100µm. (b) Analysis of total thymic cellularity, and CD4 and CD8 expression on thymocytes of one week old iFoxn1Δ7,8 mice exposed to Doxycycline (Dox+) or saline (Dox-) 3 days earlier. (c) Analysis of total thymic cellularity, and CD4 and CD8 expression on all thymocytes as well as c-kit and CD25 expression on CD4-CD8-Lin- thymocytes isolated from one week old iFoxn1Δ7,8 mice exposed to Doxycycline (Dox+) or saline (Dox-) 4 days earlier. *p<0.0. (student’s t-test (a-c). Data are from two (a-c) independent experiments with sample sizes of three. Data (mean ±SD) is pooled for display in bar graphs (b, c). Contour plots (b,c) are representative of data in corresponding bar graphs. Numbers shown in individual gates and quadrants of flow cytometry plots represent the frequencies observed in a representative experiment.

Supplementary Figure 7 Principal component analysis.

(a) Principal component analysis of RNA-seq datasets from cTEC and mTEC of Foxn1wt*/- and Foxn1wt*/wt* mice. (b) Principal component analysis of RNA-seq datasets from cTEC isolated from Dox-treated iFoxn1Δ7,8 mice and iFoxn1Δ7,8 mice that lack the Cre-recombinase.

Supplementary Figure 8 Integration of ChIP-seq and RNA-seq datasets.

BETA analysis of Foxn1 function by integration of ChIP-seq data sets and data sets from cTEC of Dox-treated iFoxn1Δ7,8 mice with the TetO-Cre transgene (designated here TetO+) vs. iFoxn1Δ7,8 mice that lack the TetO-Cre transgene (designated TetO-). Cumulative proportion of genes either upregulated (red), downregulated (blue) or unchanged (black) by increased levels of active Foxn1 against different regulatory score cut-offs.

Supplementary Figure 9 Linear relationship between relative expression of Foxn1-binding exons and Foxn1 target-gene expression.

(a) All high confidence Foxn1 gene targets. Overall mean gene expression is shown in dark red (r2=0.92, p<0.0001). (b) Ccl25 (r2=0.95, p<0.0001). (c) Dll4 (r2=0.90, p<0.0001). (d) Cd83 (r2=0.92, p<0.0001). Relative Foxn1 DNA binding exon expression was calculated as the mean number of reads aligned to the Foxn1 DNA binding exons 7 and 8 normalized by RNA-seq library size and overall Foxn1 expression.

Supplementary Figure 10 Comparative analysis of differential gene expression in cTECs.

Scatter plot of log2 fold change in gene expression in cTEC data sets from Foxn1wt*/- vs. Foxn1wt*/wt* mice and from Dox-treated iFoxn1Δ7,8 mice with TetO-Cre transgene (designated here TetO+) vs. iFoxn1Δ7,8 mice that lack the TetO-Cre transgene (designated TetO-). Genes significantly changed in both models at FDR < 0.05 are highlighted in red. Positive fold change indicates higher expression in Foxn1wt*/wt* mice than Foxn1wt*/- or TetO-iFoxn1Δ7,8 than TetO+ iFoxn1Δ7,8, respectively.

Supplementary Figure 11 Weighted correlation network analysis (WGCNA).

(a) Network permutation analysis showing median bidirectional weighted correlation coefficients for the high confidence Foxn1 gene targets and randomly selected genes matched by expression decile. This co-expression network includes only TEC data (cTEC, mTEClo and mTEChi). The vertical red line indicates real data. (b) Soft threshold r2 for different threshold powers. (c) Cluster dendrogram depicting WGCNA gene modules.

Supplementary Figure 12 Network analysis and assessment of putative binding partners.

(a) A direct seed co-expression network for cTEC generated from TEC-specific microarray data23. Interactions are shown for r2 > 0.7. The local network surrounding Foxn1 (yellow) is shown in the magnified graphic view. This network includes only cTEC data. (b) Likely binding partners of Foxn1 detected by PScan ChIP local motif enrichment. Specific motif IDs are CREB1_MA0018.1, TP63_MA0525.1, Mycn_MA0104.2, Bach1::Mafk_MA0591.1, NRF1_MA0506.1, HIF1A::ARNT_MA0259.1, REST_MA0138.2, E2F1_MA0024.2 and Mafb_MA0117.1. (c) Motif enrichment for binding motifs for several PScan predicted binding partners near Foxn1 ChIP-seq peaks. Enrichment is shown relative to the mean coverage near Foxn1 ChIP-seq peaks.

Supplementary Figure 13 Reduced Psmb11 expression in Foxn1wt*/– mice.

Immunofluorescence analysis for Psmb11(green) and CD4 (red) expression in thymus tissue sections of 1 week old mice with indicated genotype. Scale bar 50µm. The data is representative of two independent experiments analyzing 2 mice per group.

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Žuklys, S., Handel, A., Zhanybekova, S. et al. Foxn1 regulates key target genes essential for T cell development in postnatal thymic epithelial cells. Nat Immunol 17, 1206–1215 (2016). https://doi.org/10.1038/ni.3537

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