#PAGE_PARAMS# #ADS_HEAD_SCRIPTS# #MICRODATA#

Functional Genomic Analysis of the Regulatory Network in


The let-7 microRNA (miRNA) regulates cellular differentiation across many animal species. Loss of let-7 activity causes abnormal development in Caenorhabditis elegans and unchecked cellular proliferation in human cells, which contributes to tumorigenesis. These defects are due to improper expression of protein-coding genes normally under let-7 regulation. While some direct targets of let-7 have been identified, the genome-wide effect of let-7 insufficiency in a developing animal has not been fully investigated. Here we report the results of molecular and genetic assays aimed at determining the global network of genes regulated by let-7 in C. elegans. By screening for mis-regulated genes that also contribute to let-7 mutant phenotypes, we derived a list of physiologically relevant potential targets of let-7 regulation. Twenty new suppressors of the rupturing vulva or extra seam cell division phenotypes characteristic of let-7 mutants emerged. Three of these genes, opt-2, prmt-1, and T27D12.1, were found to associate with Argonaute in a let-7–dependent manner and are likely novel direct targets of this miRNA. Overall, a complex network of genes with various activities is subject to let-7 regulation to coordinate developmental timing across tissues during worm development.


Vyšlo v časopise: Functional Genomic Analysis of the Regulatory Network in. PLoS Genet 9(3): e32767. doi:10.1371/journal.pgen.1003353
Kategorie: Research Article
prolekare.web.journal.doi_sk: https://doi.org/10.1371/journal.pgen.1003353

Souhrn

The let-7 microRNA (miRNA) regulates cellular differentiation across many animal species. Loss of let-7 activity causes abnormal development in Caenorhabditis elegans and unchecked cellular proliferation in human cells, which contributes to tumorigenesis. These defects are due to improper expression of protein-coding genes normally under let-7 regulation. While some direct targets of let-7 have been identified, the genome-wide effect of let-7 insufficiency in a developing animal has not been fully investigated. Here we report the results of molecular and genetic assays aimed at determining the global network of genes regulated by let-7 in C. elegans. By screening for mis-regulated genes that also contribute to let-7 mutant phenotypes, we derived a list of physiologically relevant potential targets of let-7 regulation. Twenty new suppressors of the rupturing vulva or extra seam cell division phenotypes characteristic of let-7 mutants emerged. Three of these genes, opt-2, prmt-1, and T27D12.1, were found to associate with Argonaute in a let-7–dependent manner and are likely novel direct targets of this miRNA. Overall, a complex network of genes with various activities is subject to let-7 regulation to coordinate developmental timing across tissues during worm development.


Zdroje

1. AaltoAP, PasquinelliAE (2012) Small non-coding RNAs mount a silent revolution in gene expression. Curr Opin in Cell Biol 24 (3)

333–40 doi:10.1016/j.ceb.2012.03.006.

2. KimVN, HanJ, SiomiMC (2009) Biogenesis of small RNAs in animals. Nature reviews Molecular cell biology 10: 126–139.

3. WinterJ, JungS, KellerS, GregoryRI, DiederichsS (2009) Many roads to maturity: microRNA biogenesis pathways and their regulation. Nature cell biology 11: 228–234.

4. HuntzingerE, IzaurraldeE (2011) Gene silencing by microRNAs: contributions of translational repression and mRNA decay. Nature reviews Genetics 12: 99–110.

5. PasquinelliAE (2012) MicroRNAs and their targets: recognition, regulation and an emerging reciprocal relationship. Nature reviews Genetics 13: 271–282.

6. ReinhartBJ, SlackFJ, BassonM, PasquinelliAE, BettingerJC, et al. (2000) The 21-nucleotide let-7 RNA regulates developmental timing in Caenorhabditis elegans. Nature 403: 901–906.

7. SlackFJ, BassonM, LiuZ, AmbrosV, HorvitzHR, et al. (2000) The lin-41 RBCC gene acts in the C. elegans heterochronic pathway between the let-7 regulatory RNA and the LIN-29 transcription factor. Molecular cell 5: 659–669.

8. AmbrosV, HorvitzHR (1984) Heterochronic mutants of the nematode Caenorhabditis elegans. Science 226: 409–416.

9. AbrahanteJE, DaulAL, LiM, VolkML, TennessenJM, et al. (2003) The Caenorhabditis elegans hunchback-like gene lin-57/hbl-1 controls developmental time and is regulated by microRNAs. Developmental cell 4: 625–637.

10. LinSY, JohnsonSM, AbrahamM, VellaMC, PasquinelliA, et al. (2003) The C elegans hunchback homolog, hbl-1, controls temporal patterning and is a probable microRNA target. Developmental cell 4: 639–650.

11. GrosshansH, JohnsonT, ReinertKL, GersteinM, SlackFJ (2005) The temporal patterning microRNA let-7 regulates several transcription factors at the larval to adult transition in C. elegans. Developmental cell 8: 321–330.

12. PasquinelliAE, ReinhartBJ, SlackF, MartindaleMQ, KurodaMI, et al. (2000) Conservation of the sequence and temporal expression of let-7 heterochronic regulatory RNA. Nature 408: 86–89.

13. MondolV, PasquinelliAE (2012) Let's make it happen: the role of let-7 microRNA in development. Current topics in developmental biology 99: 1–30.

14. BoyerinasB, ParkSM, HauA, MurmannAE, PeterME (2010) The role of let-7 in cell differentiation and cancer. Endocrine-related cancer 17: F19–36.

15. ThorntonJE, GregoryRI (2012) How does Lin28 let-7 control development and disease? Trends Cell Biol 474–82 doi:10.1016/j.tcb.2012.06.001.

16. HeoI, JooC, ChoJ, HaM, HanJ, et al. (2008) Lin28 mediates the terminal uridylation of let-7 precursor MicroRNA. Molecular cell 32: 276–284.

17. NewmanMA, ThomsonJM, HammondSM (2008) Lin-28 interaction with the Let-7 precursor loop mediates regulated microRNA processing. RNA 14: 1539–1549.

18. RybakA, FuchsH, SmirnovaL, BrandtC, PohlEE, et al. (2008) A feedback loop comprising lin-28 and let-7 controls pre-let-7 maturation during neural stem-cell commitment. Nature cell biology 10: 987–993.

19. ViswanathanSR, DaleyGQ, GregoryRI (2008) Selective blockade of microRNA processing by Lin28. Science 320: 97–100.

20. HeoI, JooC, KimYK, HaM, YoonMJ, et al. (2009) TUT4 in concert with Lin28 suppresses microRNA biogenesis through pre-microRNA uridylation. Cell 138: 696–708.

21. LehrbachNJ, ArmisenJ, LightfootHL, MurfittKJ, BugautA, et al. (2009) LIN-28 and the poly(U) polymerase PUP-2 regulate let-7 microRNA processing in Caenorhabditis elegans. Nature structural & molecular biology 16: 1016–1020.

22. PiskounovaE, PolytarchouC, ThorntonJE, LaPierreRJ, PothoulakisC, et al. (2011) Lin28A and Lin28B inhibit let-7 microRNA biogenesis by distinct mechanisms. Cell 147: 1066–1079.

23. Van WynsberghePM, KaiZS, MassirerKB, BurtonVH, YeoGW, et al. (2011) LIN-28 co-transcriptionally binds primary let-7 to regulate miRNA maturation in Caenorhabditis elegans. Nature structural & molecular biology 18: 302–308.

24. ViswanathanSR, PowersJT, EinhornW, HoshidaY, NgTL, et al. (2009) Lin28 promotes transformation and is associated with advanced human malignancies. Nature genetics 41: 843–848.

25. ZhuH, Shyh-ChangN, SegreAV, ShinodaG, ShahSP, et al. (2011) The Lin28/let-7 axis regulates glucose metabolism. Cell 147: 81–94.

26. FrostRJ, OlsonEN (2011) Control of glucose homeostasis and insulin sensitivity by the Let-7 family of microRNAs. Proceedings of the National Academy of Sciences of the United States of America 108: 21075–21080.

27. JohnsonSM, GrosshansH, ShingaraJ, ByromM, JarvisR, et al. (2005) RAS is regulated by the let-7 microRNA family. Cell 120: 635–647.

28. JohnsonCD, Esquela-KerscherA, StefaniG, ByromM, KelnarK, et al. (2007) The let-7 microRNA represses cell proliferation pathways in human cells. Cancer research 67: 7713–7722.

29. BoyerinasB, ParkSM, ShomronN, HedegaardMM, VintherJ, et al. (2008) Identification of let-7-regulated oncofetal genes. Cancer research 68: 2587–2591.

30. ShellS, ParkSM, RadjabiAR, SchickelR, KistnerEO, et al. (2007) Let-7 expression defines two differentiation stages of cancer. Proceedings of the National Academy of Sciences of the United States of America 104: 11400–11405.

31. YuF, YaoH, ZhuP, ZhangX, PanQ, et al. (2007) let-7 regulates self renewal and tumorigenicity of breast cancer cells. Cell 131: 1109–1123.

32. LeeYS, DuttaA (2007) The tumor suppressor microRNA let-7 represses the HMGA2 oncogene. Genes & development 21: 1025–1030.

33. MayrC, HemannMT, BartelDP (2007) Disrupting the pairing between let-7 and Hmga2 enhances oncogenic transformation. Science 315: 1576–1579.

34. Esquela-KerscherA, TrangP, WigginsJF, PatrawalaL, ChengA, et al. (2008) The let-7 microRNA reduces tumor growth in mouse models of lung cancer. Cell cycle 7: 759–764.

35. KumarMS, ErkelandSJ, PesterRE, ChenCY, EbertMS, et al. (2008) Suppression of non-small cell lung tumor development by the let-7 microRNA family. Proceedings of the National Academy of Sciences of the United States of America 105: 3903–3908.

36. EnrightAJ, JohnB, GaulU, TuschlT, SanderC, et al. (2003) MicroRNA targets in Drosophila. Genome biology 5: R1.

37. LewisBP, ShihIH, Jones-RhoadesMW, BartelDP, BurgeCB (2003) Prediction of mammalian microRNA targets. Cell 115: 787–798.

38. LallS, GrunD, KrekA, ChenK, WangYL, et al. (2006) A genome-wide map of conserved microRNA targets in C. elegans. Current biology : CB 16: 460–471.

39. MirandaKC, HuynhT, TayY, AngYS, TamWL, et al. (2006) A pattern-based method for the identification of MicroRNA binding sites and their corresponding heteroduplexes. Cell 126: 1203–1217.

40. KerteszM, IovinoN, UnnerstallU, GaulU, SegalE (2007) The role of site accessibility in microRNA target recognition. Nature genetics 39: 1278–1284.

41. HammellM, LongD, ZhangL, LeeA, CarmackCS, et al. (2008) mirWIP: microRNA target prediction based on microRNA-containing ribonucleoprotein-enriched transcripts. Nature methods 5: 813–819.

42. BartelDP (2009) MicroRNAs: target recognition and regulatory functions. Cell 136: 215–233.

43. ShinC, NamJW, FarhKK, ChiangHR, ShkumatavaA, et al. (2010) Expanding the microRNA targeting code: functional sites with centered pairing. Molecular cell 38: 789–802.

44. RigoutsosI (2009) New tricks for animal microRNAS: targeting of amino acid coding regions at conserved and nonconserved sites. Cancer research 69: 3245–3248.

45. WightmanB, HaI, RuvkunG (1993) Posttranscriptional regulation of the heterochronic gene lin-14 by lin-4 mediates temporal pattern formation in C. elegans. Cell 75: 855–862.

46. LeeRC, FeinbaumRL, AmbrosV (1993) The C. elegans heterochronic gene lin-4 encodes small RNAs with antisense complementarity to lin-14. Cell 75: 843–854.

47. ThomsonDW, BrackenCP, GoodallGJ (2011) Experimental strategies for microRNA target identification. Nucleic acids research 39: 6845–6853.

48. HuangJC, BabakT, CorsonTW, ChuaG, KhanS, et al. (2007) Using expression profiling data to identify human microRNA targets. Nature methods 4: 1045–1049.

49. LimLP, LauNC, Garrett-EngeleP, GrimsonA, SchelterJM, et al. (2005) Microarray analysis shows that some microRNAs downregulate large numbers of target mRNAs. Nature 433: 769–773.

50. SchmitterD, FilkowskiJ, SewerA, PillaiRS, OakeleyEJ, et al. (2006) Effects of Dicer and Argonaute down-regulation on mRNA levels in human HEK293 cells. Nucleic acids research 34: 4801–4815.

51. SoodP, KrekA, ZavolanM, MacinoG, RajewskyN (2006) Cell-type-specific signatures of microRNAs on target mRNA expression. Proceedings of the National Academy of Sciences of the United States of America 103: 2746–2751.

52. BaekD, VillenJ, ShinC, CamargoFD, GygiSP, et al. (2008) The impact of microRNAs on protein output. Nature 455: 64–71.

53. SelbachM, SchwanhausserB, ThierfelderN, FangZ, KhaninR, et al. (2008) Widespread changes in protein synthesis induced by microRNAs. Nature 455: 58–63.

54. JovanovicM, ReiterL, PicottiP, LangeV, BoganE, et al. (2010) A quantitative targeted proteomics approach to validate predicted microRNA targets in C. elegans. Nature methods 7: 837–842.

55. GuoH, IngoliaNT, WeissmanJS, BartelDP (2010) Mammalian microRNAs predominantly act to decrease target mRNA levels. Nature 466: 835–840.

56. StadlerM, ArtilesK, PakJ, FireA (2012) Contributions of mRNA abundance, ribosome loading, and post- or peri-translational effects to temporal repression of C. elegans heterochronic miRNA targets. Genome Res 22 (12)

2418–26 doi:10.1101/gr.136515.111.

57. BeitzingerM, PetersL, ZhuJY, KremmerE, MeisterG (2007) Identification of human microRNA targets from isolated argonaute protein complexes. RNA biology 4: 76–84.

58. EasowG, TelemanAA, CohenSM (2007) Isolation of microRNA targets by miRNP immunopurification. RNA 13: 1198–1204.

59. HendricksonDG, HoganDJ, HerschlagD, FerrellJE, BrownPO (2008) Systematic identification of mRNAs recruited to argonaute 2 by specific microRNAs and corresponding changes in transcript abundance. PLoS ONE 3: e2126 doi:10.1371/journal.pone.0002126.

60. KarginovFV, ConacoC, XuanZ, SchmidtBH, ParkerJS, et al. (2007) A biochemical approach to identifying microRNA targets. Proceedings of the National Academy of Sciences of the United States of America 104: 19291–19296.

61. LandthalerM, GaidatzisD, RothballerA, ChenPY, SollSJ, et al. (2008) Molecular characterization of human Argonaute-containing ribonucleoprotein complexes and their bound target mRNAs. RNA 14: 2580–2596.

62. ZhangL, DingL, CheungTH, DongMQ, ChenJ, et al. (2007) Systematic identification of C. elegans miRISC proteins, miRNAs, and mRNA targets by their interactions with GW182 proteins AIN-1 and AIN-2. Molecular cell 28: 598–613.

63. ChiSW, ZangJB, MeleA, DarnellRB (2009) Argonaute HITS-CLIP decodes microRNA-mRNA interaction maps. Nature 460: 479–486.

64. HafnerM, LandthalerM, BurgerL, KhorshidM, HausserJ, et al. (2010) Transcriptome-wide identification of RNA-binding protein and microRNA target sites by PAR-CLIP. Cell 141: 129–141.

65. LeungAK, YoungAG, BhutkarA, ZhengGX, BossonAD, et al. (2011) Genome-wide identification of Ago2 binding sites from mouse embryonic stem cells with and without mature microRNAs. Nature structural & molecular biology 18: 237–244.

66. ZisoulisDG, LovciMT, WilbertML, HuttKR, LiangTY, et al. (2010) Comprehensive discovery of endogenous Argonaute binding sites in Caenorhabditis elegans. Nature structural & molecular biology 17: 173–179.

67. BaggaS, BrachtJ, HunterS, MassirerK, HoltzJ, et al. (2005) Regulation by let-7 and lin-4 miRNAs results in target mRNA degradation. Cell 122: 553–563.

68. DingXC, GrosshansH (2009) Repression of C. elegans microRNA targets at the initiation level of translation requires GW182 proteins. The EMBO journal 28: 213–222.

69. LewisBP, BurgeCB, BartelDP (2005) Conserved seed pairing, often flanked by adenosines, indicates that thousands of human genes are microRNA targets. Cell 120: 15–20.

70. VellaMC, ChoiEY, LinSY, ReinertK, SlackFJ (2004) The C. elegans microRNA let-7 binds to imperfect let-7 complementary sites from the lin-41 3′UTR. Genes & development 18: 132–137.

71. NimmoRA, SlackFJ (2009) An elegant miRror: microRNAs in stem cells, developmental timing and cancer. Chromosoma 118: 405–418.

72. BettingerJC, LeeK, RougvieAE (1996) Stage-specific accumulation of the terminal differentiation factor LIN-29 during Caenorhabditis elegans development. Development 122: 2517–2527.

73. RougvieAE, AmbrosV (1995) The heterochronic gene lin-29 encodes a zinc finger protein that controls a terminal differentiation event in Caenorhabditis elegans. Development 121: 2491–2500.

74. DingXC, SlackFJ, GrosshansH (2008) The let-7 microRNA interfaces extensively with the translation machinery to regulate cell differentiation. Cell cycle 7: 3083–3090.

75. KamathRS, FraserAG, DongY, PoulinG, DurbinR, et al. (2003) Systematic functional analysis of the Caenorhabditis elegans genome using RNAi. Nature 421: 231–237.

76. RualJF, CeronJ, KorethJ, HaoT, NicotAS, et al. (2004) Toward improving Caenorhabditis elegans phenome mapping with an ORFeome-based RNAi library. Genome research 14: 2162–2168.

77. SternbergPW (2005) Vulval development. WormBook : the online review of C elegans biology 1–28.

78. SherwoodDR, ButlerJA, KramerJM, SternbergPW (2005) FOS-1 promotes basement-membrane removal during anchor-cell invasion in C. elegans. Cell 121: 951–962.

79. MohamadnejadM, SwensonES (2008) Induced pluripotent cells mimicking human embryonic stem cells. Archives of Iranian medicine 11: 125–128.

80. YuJ, VodyanikMA, Smuga-OttoK, Antosiewicz-BourgetJ, FraneJL, et al. (2007) Induced pluripotent stem cell lines derived from human somatic cells. Science 318: 1917–1920.

81. TayY, ZhangJ, ThomsonAM, LimB, RigoutsosI (2008) MicroRNAs to Nanog, Oct4 and Sox2 coding regions modulate embryonic stem cell differentiation. Nature 455: 1124–1128.

82. HayesGD, FrandAR, RuvkunG (2006) The mir-84 and let-7 paralogous microRNA genes of Caenorhabditis elegans direct the cessation of molting via the conserved nuclear hormone receptors NHR-23 and NHR-25. Development 133: 4631–4641.

83. SulstonJE, HorvitzHR (1977) Post-embryonic cell lineages of the nematode, Caenorhabditis elegans. Developmental biology 56: 110–156.

84. SmithJA, McGarrP, GilleardJS (2005) The Caenorhabditis elegans GATA factor elt-1 is essential for differentiation and maintenance of hypodermal seam cells and for normal locomotion. Journal of cell science 118: 5709–5719.

85. AbbottAL, Alvarez-SaavedraE, MiskaEA, LauNC, BartelDP, et al. (2005) The let-7 MicroRNA family members mir-48, mir-84, and mir-241 function together to regulate developmental timing in Caenorhabditis elegans. Developmental cell 9: 403–414.

86. BethkeA, FielenbachN, WangZ, MangelsdorfDJ, AntebiA (2009) Nuclear hormone receptor regulation of microRNAs controls developmental progression. Science 324: 95–98.

87. HammellCM, KarpX, AmbrosV (2009) A feedback circuit involving let-7-family miRNAs and DAF-12 integrates environmental signals and developmental timing in Caenorhabditis elegans. Proceedings of the National Academy of Sciences of the United States of America 106: 18668–18673.

88. ZisoulisDG, KaiZS, ChangRK, PasquinelliAE (2012) Autoregulation of microRNA biogenesis by let-7 and Argonaute. Nature 486: 541–544.

89. BussingI, SlackFJ, GrosshansH (2008) let-7 microRNAs in development, stem cells and cancer. Trends in molecular medicine 14: 400–409.

90. RoushSF, SlackFJ (2009) Transcription of the C. elegans let-7 microRNA is temporally regulated by one of its targets, hbl-1. Developmental biology 334: 523–534.

91. MeissnerB, BollM, DanielH, BaumeisterR (2004) Deletion of the intestinal peptide transporter affects insulin and TOR signaling in Caenorhabditis elegans. The Journal of biological chemistry 279: 36739–36745.

92. VeljkovicE, StasiukS, SkellyPJ, ShoemakerCB, VerreyF (2004) Functional characterization of Caenorhabditis elegans heteromeric amino acid transporters. The Journal of biological chemistry 279: 7655–7662.

93. YamagataK, DaitokuH, TakahashiY, NamikiK, HisatakeK, et al. (2008) Arginine methylation of FOXO transcription factors inhibits their phosphorylation by Akt. Molecular cell 32: 221–231.

94. NehrkeK (2003) A reduction in intestinal cell pHi due to loss of the Caenorhabditis elegans Na+/H+ exchanger NHX-2 increases life span. The Journal of biological chemistry 278: 44657–44666.

95. SpanierB, LaschK, MarschS, BennerJ, LiaoW, et al. (2009) How the intestinal peptide transporter PEPT-1 contributes to an obesity phenotype in Caenorhabditits elegans. PLoS ONE 4: e6279 doi:10.1371/journal.pone.0006279.

96. Esquela-KerscherA, JohnsonSM, BaiL, SaitoK, PartridgeJ, et al. (2005) Post-embryonic expression of C. elegans microRNAs belonging to the lin-4 and let-7 families in the hypodermis and the reproductive system. Developmental dynamics : an official publication of the American Association of Anatomists 234: 868–877.

97. JohnsonSM, LinSY, SlackFJ (2003) The time of appearance of the C. elegans let-7 microRNA is transcriptionally controlled utilizing a temporal regulatory element in its promoter. Developmental biology 259: 364–379.

98. MartinezNJ, OwMC, Reece-HoyesJS, BarrasaMI, AmbrosVR, et al. (2008) Genome-scale spatiotemporal analysis of Caenorhabditis elegans microRNA promoter activity. Genome research 18: 2005–2015.

99. StrahlBD, BriggsSD, BrameCJ, CaldwellJA, KohSS, et al. (2001) Methylation of histone H4 at arginine 3 occurs in vivo and is mediated by the nuclear receptor coactivator PRMT1. Current biology : CB 11: 996–1000.

100. WangH, HuangZQ, XiaL, FengQ, Erdjument-BromageH, et al. (2001) Methylation of histone H4 at arginine 3 facilitating transcriptional activation by nuclear hormone receptor. Science 293: 853–857.

101. TakahashiY, DaitokuH, HirotaK, TamiyaH, YokoyamaA, et al. (2011) Asymmetric arginine dimethylation determines life span in C. elegans by regulating forkhead transcription factor DAF-16. Cell metabolism 13: 505–516.

102. BrennerS (1974) The genetics of Caenorhabditis elegans. Genetics 77: 71–94.

103. IrizarryRA, HobbsB, CollinF, Beazer-BarclayYD, AntonellisKJ, et al. (2003) Exploration, normalization, and summaries of high density oligonucleotide array probe level data. Biostatistics 4: 249–264.

104. Huang daW, ShermanBT, LempickiRA (2009) Systematic and integrative analysis of large gene lists using DAVID bioinformatics resources. Nature protocols 4: 44–57.

105. Huang daW, ShermanBT, LempickiRA (2009) Bioinformatics enrichment tools: paths toward the comprehensive functional analysis of large gene lists. Nucleic acids research 37: 1–13.

106. YeoGW, Van NostrandEL, LiangTY (2007) Discovery and analysis of evolutionarily conserved intronic splicing regulatory elements. PLoS Genet 3: e85 doi:10.1371/journal.pgen.0030085.

Štítky
Genetika Reprodukčná medicína

Článok vyšiel v časopise

PLOS Genetics


2013 Číslo 3
Najčítanejšie tento týždeň
Najčítanejšie v tomto čísle
Kurzy

Zvýšte si kvalifikáciu online z pohodlia domova

Aktuální možnosti diagnostiky a léčby litiáz
nový kurz
Autori: MUDr. Tomáš Ürge, PhD.

Všetky kurzy
Prihlásenie
Zabudnuté heslo

Zadajte e-mailovú adresu, s ktorou ste vytvárali účet. Budú Vám na ňu zasielané informácie k nastaveniu nového hesla.

Prihlásenie

Nemáte účet?  Registrujte sa

#ADS_BOTTOM_SCRIPTS#