Direct Reprogramming of Human Primordial Germ Cells into Induced Pluripotent Stem Cells: Efficient Generation of Genetically Engineered Germ Cells

Stem Cells and Development

Volumn 24, Issue 22, 2015, Pages 2634-2648

  Bazley, Faith A ^a   Liu, Cyndi F ^a   Yuan, Xuan ^a   Hao, Haiping ^b   All, Angelo H ^a   De Los Angeles, Alejandro ^c,d,e   Zambidis, Elias T ^a,f   Gearhart, John D ^g,h   Kerr, Candace L ^a,i  

^a JOHNS HOPKINS UNIVERSITY SCHOOL OF MEDICINE   (United States)

^b JOHNS HOPKINS UNIVERSITY   (United States)

^c BOSTON CHILDREN S HOSPITAL   (United States)

^d HARVARD MEDICAL SCHOOL   (United States)

^e HARVARD STEM CELL INSTITUTE   (United States)

^f JOHNS HOPKINS UNIVERSITY   (United States)

^g UNIVERSITY OF PENNSYLVANIA   (United States)

^h UNIVERSITY OF PENNSYLVANIA SCHOOL OF VETERINARY MEDICINE   (United States)

ⁱ UNIVERSITY OF MARYLAND SCHOOL OF MEDICINE   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

KRUPPEL LIKE FACTOR 4; LENTIVIRUS VECTOR; LEUKEMIA INHIBITORY FACTOR; MYC PROTEIN; OCTAMER TRANSCRIPTION FACTOR 4; RNA; TRANSCRIPTION FACTOR SOX2; KRUPPEL LIKE FACTOR; POU5F1 PROTEIN, HUMAN; SOX2 PROTEIN, HUMAN; TRANSCRIPTION FACTOR SOX;

ANIMAL CELL; ARTICLE; CELL DIFFERENTIATION; CELL ENGINEERING; CONTROLLED STUDY; EMBRYO; FEMALE; GENETIC TRANSFECTION; GERM LAYER; HUMAN; HUMAN CELL; HUMAN TISSUE; IMMUNOHISTOCHEMISTRY; IN VITRO STUDY; MALE; MOUSE; NONHUMAN; NUCLEAR REPROGRAMMING; PLURIPOTENT STEM CELL; PRIMORDIAL GERM CELL; PRIORITY JOURNAL; SOMATIC CELL; TERATOMA; CELL CULTURE; CYTOLOGY; EMBRYONIC STEM CELL; GENETICS; GERM CELL; INDUCED PLURIPOTENT STEM CELL; METABOLISM;

CELLS, CULTURED; CELLULAR REPROGRAMMING; EMBRYONIC STEM CELLS; GERM CELLS; HUMANS; INDUCED PLURIPOTENT STEM CELLS; KRUPPEL-LIKE TRANSCRIPTION FACTORS; OCTAMER TRANSCRIPTION FACTOR-3; PROTO-ONCOGENE PROTEINS C-MYC; SOXB1 TRANSCRIPTION FACTORS;

EID: 84947092974     PISSN: 15473287     EISSN: 15578534     Source Type: Journal    
DOI: 10.1089/scd.2015.0100     Document Type: Article

References (90)

1. Seki Y, K Hayashi, K Itoh, M Mizugaki, M Saitou and Y Matsui. (2005). Extensive and orderly reprogramming of genome-wide chromatin modifications associated with specification and early development of germ cells in mice. Dev Biol 278:440-458.
2. Gkountela S, Z Li, JJ Vincent, KX Zhang, A Chen, M Pellegrini and AT Clark. (2012). The ontogeny of cKIT(+) human primordial germ cells proves to be a resource for human germ line reprogramming, imprint erasure and in vitro differentiation. Nat Cell Biol 15:113-122.
3. Hajkova P, K Ancelin, T Waldmann, N Lacoste, UC Lange, F Cesari, C Lee, G Almouzni, R Schneider and MA Surani. (2008). Chromatin dynamics during epigenetic reprogramming in the mouse germ line. Nature 452:877-881.
4. Popp C, W Dean, S Feng, SJ Cokus, S Andrews, M Pellegrini, SE Jacobsen and W Reik. (2010). Genomewide erasure of DNA methylation in mouse primordial germ cells is affected by AID deficiency. Nature 463: 1101-1105.
5. Urven L, D Weng, A Schumaker, J Gearhart and J McCarrey. (1993). Differential gene expression in fetal mouse germ cells. Biol Reprod 48:564-574.
6. Donovan PJ and MP de Miguel. (2003). Turning germ cells into stem cells. Curr Opin Genet Dev 13:463-471.
7. Gearhart J. (1998). New potential for human embryonic stem cells. Science 282:1061-1062.
8. Thomson JA and JS Odorico. (2000). Human embryonic stem cell and embryonic germ cell lines. Trends Biotechnol 18:53-57.
9. Swelstad BB and LK Candace. (2009). Current protocols in the generation of pluripotent stem cells: theoretical methodological and clinical considerations. Stem Cell Cloning 2010:13-27.
10. De Miguel MP, F Arnalich Montiel, P Lopez Iglesias, A Blazquez Martinez and M Nistal. (2009). Epiblast-derived stem cells in embryonic and adult tissues. Int J Dev Biol 53:1529-1540.
11. Kerr CL, MJ Shamblott and JD Gearhart. (2006). Pluripotent stem cells from germ cells. Methods Enzymol 419:400-426.
12. Byrne JA, HN Nguyen and RA Reijo Pera. (2009). Enhanced generation of induced pluripotent stem cells from a subpopulation of human fibroblasts. PLoS One 4:e7118.
13. Stadtfeld M, N Maherali, M Borkent and K Hochedlinger. (2010). A reprogrammable mouse strain from gene-targeted embryonic stem cells. Nat Methods 7:53-55.
14. Resnick JL, LS Bixler, L Cheng and PJ Donovan. (1992). Long-term proliferation of mouse primordial germ cells in culture. Nature 359:550-551.
15. Durcova-Hills G, J Ainscough and A McLaren. (2001). Pluripotential stem cells derived from migrating primordial germ cells. Differentiation 68:220-226.
16. Yeom YI, G Fuhrmann, CE Ovitt, A Brehm, K Ohbo, M Gross, K Hubner and H Scholer. (1996). Germline regulatory element of Oct-4 specific for the totipotent cycle of embryonal cells. Development 122:881-894.
17. Durcova-Hills G, IR Adams, SC Barton, MA Surani and A McLaren. (2006). The role of exogenous fibroblast growth factor-2 on the reprogramming of primordial germ cells into pluripotent stem cells. Stem Cells 24:1441-1449.
18. Na J, J Plews, J Li, P Wongtrakoongate, T Tuuri, A Feki, PW Andrews and C Unger. (2010). Molecular mechanisms of pluripotency and reprogramming. Stem Cell Res Ther 1:33.
19. Kerr CL and L Cheng. (2010). Multiple, interconvertible states of human pluripotent stem cells. Cell Stem Cell 6:497-499.
20. Buecker C, HH Chen, JM Polo, L Daheron, L Bu, TS Barakat, P Okwieka, A Porter, J Gribnau, K Hochedlinger and N Geijsen. (2010). A murine ESC-like state facilitates transgenesis and homologous recombination in human pluripotent stem cells. Cell Stem Cell 6:535-546.
21. Yamanaka S and K Takahashi. (2006). [Induction of pluripotent stem cells from mouse fibroblast cultures]. Tanpakushitsu Kakusan Koso 51:2346-2351.
22. Brambrink T, R Foreman, GG Welstead, CJ Lengner, M Wernig, H Suh and R Jaenisch. (2008). Sequential expression of pluripotency markers during direct reprogramming of mouse somatic cells. Cell Stem Cell 2:151-159.
23. Chaerkady R, CL Kerr, K Kandasamy, A Marimuthu, JD Gearhart and A Pandey. (2010). Comparative proteomics of human embryonic stem cells and embryonal carcinoma cells. Proteomics 10:1359-1373.
24. Sutiwisesak R, N Kitiyanant, N Kotchabhakdi, G Felsenfeld, PW Andrews and P Wongtrakoongate. (2014). Induced pluripotency enables differentiation of human nullipotent embryonal carcinoma cells N2102Ep. Biochim Biophys Acta 1843:2611-2619.
25. Kossack N, J Meneses, S Shefi, HN Nguyen, S Chavez, C Nicholas, J Gromoll, PJ Turek and RA Reijo-Pera. (2009). Isolation and characterization of pluripotent human spermatogonial stem cell-derived cells. Stem Cells 27:138-149
26. Guan K, K Nayernia, LS Maier, S Wagner, R Dressel, JH Lee, J Nolte, F Wolf, M Li, W Engel and G Hasenfuss. (2006). Pluripotency of spermatogonial stem cells from adult mouse testis. Nature 440:1199-1203
27. Guan K, K Nayernia, LS Maier, S Wagner, R Dressel, JH Lee, J Nolte, F Wolf, M Li, W Engel and G Hasenfuss. (2006). Pluripotency of spermatogonial stem cells from adult mouse testis. Nature 440:1199-1203.
28. Kanatsu-Shinohara M, K Inoue, J Lee, M Yoshimoto, N Ogonuki, H Miki, S Baba, T Kato, Y Kazuki, et al. (2004). Generation of pluripotent stem cells from neonatal mouse testis. Cell 119:1001-1012.
29. Conrad S, M Renninger, J Hennenlotter, T Wiesner, L Just, M Bonin, W Aicher, HJ Buhring, U Mattheus, et al. (2008). Generation of pluripotent stem cells from adult human testis. Nature 456:344-349.
30. Shamblott MJ, J Axelman, S Wang, EM Bugg, JW Littlefield, PJ Donovan, PD Blumenthal, GR Huggins and JD Gearhart. (1998). Derivation of pluripotent stem cells from cultured human primordial germ cells. Proc Natl Acad Sci U S A 95:13726-13731.
31. Turnpenny L, S Brickwood, CM Spalluto, K Piper, IT Cameron, DI Wilson and NA Hanley. (2003). Derivation of human embryonic germ cells: an alternative source of pluripotent stem cells. Stem Cells 21:598-609.
32. Pashai N, H Hao, A All, S Gupta, R Chaerkady, A De Los Angeles, JD Gearhart and CL Kerr. (2012). Genome-wide profiling of pluripotent cells reveals a unique molecular signature of human embryonic germ cells. PLoS One 7:e39088.
33. Saitou M, S Kagiwada and K Kurimoto. (2012). Epigenetic reprogramming in mouse pre-implantation development and primordial germ cells. Development 139:15-31.
34. Onyango P, S Jiang, H Uejima, MJ Shamblott, JD Gearhart, H Cui and AP Feinberg. (2002). Monoallelic expression and methylation of imprinted genes in human and mouse embryonic germ cell lineages. Proc Natl Acad Sci U S A 99:10599-10604.
35. Daley GQ. (2007). Towards the generation of patientspecific pluripotent stem cells for combined gene and cell therapy of hematologic disorders. Hematology Am Soc Hematol Educ Program: 17-22.
36. Fusaki N, H Ban, A Nishiyama, K Saeki and M Hasegawa. (2009). Efficient induction of transgene-free human pluripotent stem cells using a vector based on Sendai virus, an RNA virus that does not integrate into the host genome. Proc Jpn Acad Ser B Phys Biol Sci 85:348-362.
37. Kerr CL, CM Hill, PD Blumenthal and JD Gearhart. (2008). Expression of pluripotent stem cell markers in the human fetal ovary. Hum Reprod 23:589-599.
38. Kerr CL, CM Hill, PD Blumenthal and JD Gearhart. (2008). Expression of pluripotent stem cell markers in the human fetal testis. Stem Cells 26:412-421.
39. Hiller M, C Liu, P Blumenthal, J Gearhart and C Kerr. (2011). Bone morphogenetic protein 4 mediates human embryonic germ cell derivation. Stem Cells Dev 20:351-361
40. Kerr CL, JD Gearhart, AM Elliott and PJ Donovan. (2006). Embryonic germ cells: when germ cells become stem cells. Semin Reprod Med 24:304-313
41. Kerr CL, JD Gearhart, AM Elliott and PJ Donovan. (2006). Embryonic germ cells: when germ cells become stem cells. Semin Reprod Med 24:304-313.
42. Moisan AE, RA Foster, KJ Betteridge and AC Hahnel. (2003). Dose-response of RAG2-/-/gammac-/-mice to busulfan in preparation for spermatogonial transplantation. Reproduction 126:205-216.
43. Dowey SN, X Huang, BK Chou, Z Ye and L Cheng. (2012). Generation of integration-free human induced pluripotent stem cells from postnatal blood mononuclear cells by plasmid vector expression. Nat Protoc 7:2013-2021.
44. Mali P, BK Chou, J Yen, Z Ye, J Zou, S Dowey, RA Brodsky, JE Ohm, W Yu, et al. (2010). Butyrate greatly enhances derivation of human induced pluripotent stem cells by promoting epigenetic remodeling and the expression of pluripotency-associated genes. Stem Cells 28:713-720
45. Chou BK, P Mali, X Huang, Z Ye, SN Dowey, LM Resar, C Zou, YA Zhang, J Tong and L Cheng. (2011). Efficient human iPS cell derivation by a non-integrating plasmid from blood cells with unique epigenetic and gene expression signatures. Cell Res 21:518-529
46. Chou BK, P Mali, X Huang, Z Ye, SN Dowey, LM Resar, C Zou, YA Zhang, J Tong and L Cheng. (2011). Efficient human iPS cell derivation by a non-integrating plasmid from blood cells with unique epigenetic and gene expression signatures. Cell Res 21:518-529.
47. Chan EM, S Ratanasirintrawoot, IH Park, PD Manos, YH Loh, H Huo, JD Miller, O Hartung, J Rho, et al. (2009). Live cell imaging distinguishes bona fide human iPS cells from partially reprogrammed cells. Nat Biotechnol 27:1033-1037.
48. Lieu PT, A Fontes, MC Vemuri and CC MacArthur. (2013). Generation of induced pluripotent stem cells with CytoTune, a non-integrating Sendai virus. Methods Mol Biol 997:45-56.
49. MacArthur CC, A Fontes, N Ravinder, D Kuninger, J Kaur, M Bailey, A Taliana, MC Vemuri and PT Lieu. (2012). Generation of human-induced pluripotent stem cells by a nonintegrating RNA Sendai virus vector in feeder-free or xeno-free conditions. Stem Cells Int 2012.
50. Manos PD, S Ratanasirintrawoot, S Loewer, GQ Daley and TM Schlaeger. (2011). Live-cell immunofluorescence staining of human pluripotent stem cells. Curr Protoc Stem Cell Biol Chapter 1: Unit 1C.12.
51. Irizarry RA, B Hobbs, F Collin, YD Beazer-Barclay, KJ Antonellis, U Scherf and TP Speed. (2003). Exploration, normalization, and summaries of high density oligonucleotide array probe level data. Biostatistics 4:249-264.
52. Chen G, Z Ye, X Yu, J Zou, P Mali, RA Brodsky and L Cheng. (2008). Trophoblast differentiation defect in human embryonic stem cells lacking PIG-A and GPI-anchored cell-surface proteins. Cell Stem Cell 2:345-355.
53. Pan G and JA Thomson. (2007). Nanog and transcriptional networks in embryonic stem cell pluripotency. Cell Res 17:42-49.
54. Perrett RM, L Turnpenny, JJ Eckert, M O'Shea, SB Sonne, IT Cameron, DI Wilson, E Rajpert-De Meyts and NA Hanley. (2008). The early human germ cell lineage does not express SOX2 during in vivo development or upon in vitro culture. Biol Reprod 78:852-858.
55. Hanna J, AW Cheng, K Saha, J Kim, CJ Lengner, F Soldner, JP Cassady, J Muffat, BW Carey and R Jaenisch. (2010). Human embryonic stem cells with biological and epigenetic characteristics similar to those of mouse ESCs. Proc Natl Acad Sci U S A 107:9222-9227.
56. Oue M, H Handa, Y Matsuzaki, K Suzue, H Murakami and H Hirai. (2012). The murine stem cell virus promoter drives correlated transgene expression in the leukocytes and cerebellar purkinje cells of transgenic mice. PLoS One 7:e51015.
57. Ohm JE, P Mali, L Van Neste, DM Berman, L Liang, K Pandiyan, KJ Briggs, W Zhang, P Argani, et al. (2010). Cancer-related epigenome changes associated with reprogramming to induced pluripotent stem cells. Cancer Res 70:7662-7673.
58. Park I-H, R Zhao, JA West, A Yabuuchi, H Huo, TA Ince, PH Lerou, MW Lensch and GQ Daley. (2007). Reprogramming of human somatic cells to pluripotency with defined factors. Nature 451:141-146.
59. Yu J, MA Vodyanik, K Smuga-Otto, J Antosiewicz-Bourget, JL Frane, S Tian, J Nie, GA Jonsdottir, V Ruotti, et al. (2007). Induced pluripotent stem cell lines derived from human somatic cells. Science 318:1917-1920.
60. Kim JB, H Zaehres, G Wu, L Gentile, K Ko, V Sebastiano, MJ Arauzo-Bravo, D Ruau, DW Han, M Zenke and HR Scholer. (2008). Pluripotent stem cells induced from adult neural stem cells by reprogramming with two factors. Nature 454:646-650.
61. Zhao H-x, Y Li, H-f Jin, L Xie, C Liu, F Jiang, Y-n Luo, G-w Yin, Y Li and J Wang. (2010). Rapid and efficient reprogramming of human amnion-derived cells into pluripotency by three factors OCT4/SOX2/NANOG. Differentiation 80:123-129.
62. Hansel MC, R Gramignoli, W Blake, J Davila, K Skvorak, K Dorko, V Tahan, BR Lee, E Tafaleng and J Guzman-Lepe. (2014). Increased reprogramming of human fetal hepatocytes compared with adult hepatocytes in feeder-free conditions. Cell Transplant 23:27-38.
63. Kimura T, Y Kaga, Y Sekita, K Fujikawa, T Nakatani, M Odamoto, S Funaki, M Ikawa, K Abe and T Nakano. (2015). Pluripotent stem cells derived from mouse primordial germ cells by small molecule compounds. Stem Cells 33:45-55.
64. Cheng AM, MW Byrom, J Shelton and LP Ford. (2005). Antisense inhibition of human miRNAs and indications for an involvement of miRNA in cell growth and apoptosis. Nucleic Acids Res 33:1290-1297.
65. Schlaeger TM, L Daheron, TR Brickler, S Entwisle, K Chan, A Cianci, A DeVine, A Ettenger, K Fitzgerald and M Godfrey. (2014). A comparison of non-integrating reprogramming methods. Nat Biotechnol 33:58-63.
66. Tiemann U, M Sgodda, E Warlich, M Ballmaier, HR Scholer, A Schambach and T Cantz. (2011). Optimal reprogramming factor stoichiometry increases colony numbers and affects molecular characteristics of murine induced pluripotent stem cells. Cytometry A 79: 426-435.
67. Pan G, J Li, Y Zhou, H Zheng and D Pei. (2006). A negative feedback loop of transcription factors that controls stem cell pluripotency and self-renewal. FASEB J 20:1730-1732.
68. Boyer LA, TI Lee, MF Cole, SE Johnstone, SS Levine, JP Zucker, MG Guenther, RM Kumar, HL Murray and RG Jenner. (2005). Core transcriptional regulatory circuitry in human embryonic stem cells. Cell 122:947-956.
69. Papapetrou EP, MJ Tomishima, SM Chambers, Y Mica, E Reed, J Menon, V Tabar, Q Mo, L Studer and M Sadelain. (2009). Stoichiometric and temporal requirements of Oct4, Sox2, Klf4, and c-Myc expression for efficient human iPSC induction and differentiation. Proc Natl Acad Sci U S A 106:12759-12764.
70. Oka M, T Moriyama, M Asally, K Kawakami and Y Yoneda. (2013). Differential role for transcription factor Oct4 nucleocytoplasmic dynamics in somatic cell reprogramming and self-renewal of embryonic stem cells. J Biol Chem 288:15085-15097.
71. Cauffman G, H Van de Velde, I Liebaers and A Van Steirteghem. (2004). Oct-4 mRNA and protein expression during human preimplantation development. Mol Hum Reprod 11:173-181.
72. Bhartiya D, S Kasiviswanathan, SK Unni, P Pethe, JV Dhabalia, S Patwardhan and HB Tongaonkar. (2010). Newer insights into premeiotic development of germ cells in adult human testis using Oct-4 as a stem cell marker. J Histochem Cytochem 58:1093-1106.
73. Byskov A, P Høyer, CY Andersen, S Kristensen, A Jespersen and K Møllgård. (2011). No evidence for the presence of oogonia in the human ovary after their final clearance during the first two years of life. Hum Reprod 26:2129-2139.
74. Wei Z, Y Yang, P Zhang, R Andrianakos, K Hasegawa, J Lyu, X Chen, G Bai, C Liu, M Pera and W Lu. (2009). Klf4 interacts directly with Oct4 and Sox2 to promote reprogramming. Stem Cells 27:2969-2978.
75. Chan KK, J Zhang, NY Chia, YS Chan, HS Sim, KS Tan, SK Oh, HH Ng and AB Choo. (2009). KLF4 and PBX1 directly regulate NANOG expression in human embryonic stem cells. Stem Cells 27:2114-2125.
76. Zhang P, R Andrianakos, Y Yang, C Liu and W Lu. (2010). Kruppel-like factor 4 (Klf4) prevents embryonic stem (ES) cell differentiation by regulating Nanog gene expression. J Biol Chem 285:9180-9189.
77. Nakagawa M, N Takizawa, M Narita, T Ichisaka and S Yamanaka. (2010). Promotion of direct reprogramming by transformation-deficient Myc. Proc Natl Acad Sci U S A 107:14152-14157.
78. Cartwright P, C McLean, A Sheppard, D Rivett, K Jones and S Dalton. (2005). LIF/STAT3 controls ES cell selfrenewal and pluripotency by a Myc-dependent mechanism. Development 132:885-896.
79. Okita K, Y Matsumura, Y Sato, A Okada, A Morizane, S Okamoto, H Hong, M Nakagawa, K Tanabe and K-i Tezuka. (2011). A more efficient method to generate integration-free human iPS cells. Nat Methods 8: 409-412.
80. Smith KN, AM Singh and S Dalton. (2010). Myc represses primitive endoderm differentiation in pluripotent stem cells. Cell Stem Cell 7:343-354.
81. Nagamatsu G, T Kosaka, M Kawasumi, T Kinoshita, K Takubo, H Akiyama, T Sudo, T Kobayashi, M Oya and T Suda. (2011). A germ cell-specific gene, Prmt5, works in somatic cell reprogramming. J Biol Chem 286:10641-10648.
82. Xu J, F Wang, Z Tang, Y Zhan, J Zhang, Q Yan, Y Xiong, X Xie, J Wu and S Zhang. (2010). Role of leukaemia inhibitory factor in the induction of pluripotent stem cells in mice. Cell Biol Int 34:791-797.
83. Reubinoff BE, MF Pera, CY Fong, A Trounson and A Bongso. (2000). Embryonic stem cell lines from human blastocysts: somatic differentiation in vitro. Nat Biotechnol 18:399-404.
84. Mitalipova M, J Calhoun, S Shin, D Wininger, T Schulz, S Noggle, A Venable, I Lyons, A Robins and S Stice. (2003). Human embryonic stem cell lines derived from discarded embryos. Stem Cells 21:521-526.
85. Warren L, PD Manos, T Ahfeldt, YH Loh, H Li, F Lau, W Ebina, PK Mandal, ZD Smith, et al. (2010). Highly efficient reprogramming to pluripotency and directed differentiation of human cells with synthetic modified mRNA. Cell Stem Cell 7:618-630.
86. Mikkelsen TS, J Hanna, X Zhang, M Ku, M Wernig, P Schorderet, BE Bernstein, R Jaenisch, ES Lander and A Meissner. (2008). Dissecting direct reprogramming through integrative genomic analysis. Nature 454:49-55.
87. Wutz A. (2012). Epigenetic alterations in human pluripotent stem cells: a tale of two cultures. Cell Stem Cell 11:9-15.
88. Rodda DJ, JL Chew, LH Lim, YH Loh, B Wang, HH Ng and P Robson. (2005). Transcriptional regulation of nanog by OCT4 and SOX2. J Biol Chem 280:24731-24737.
89. Wang ZX, CHL Teh, JLL Kueh, T Lufkin, P Robson and LW Stanton. (2007). Oct4 and sox2 directly regulate expression of another pluripotency transcription factor, Zfp206, in embryonic stem cells. J Biol Chem 282:12822-12830.
90. West JA, SR Viswanathan, A Yabuuchi, K Cunniff, A Takeuchi, IH Park, JE Sero, H Zhu, A Perez-Atayde, et al. (2009). A role for Lin28 in primordial germ-cell development and germ-cell malignancy. Nature 460:909-913.