Учебники / Genetic Hearing Loss Willems 2004

Figure 11 Scanning electron microscopy (SEM) of the organ of Corti reveals Pou4f3 knockout mouse abnormalities. (A, B) Stereocilia bundles of outer hair cells (OHC) and inner hair cells (IHC) are shown from a wild-type mouse. (C, D) There are no stereocilia bundles on the apical surface of the organ of Corti derived from Pou4f3 mutant mice. Scale bar = 10 Am (A and C) and 1 Am (B and D). (Reproduced with permission from Ref. 63.)

architecture and semicircular canal arrangement are normal (56). However, unlike the Math1 knockout mice that never form hair cells to begin with (17), a careful look into the ears of the Pou4f3 mutant mice at E16.5 reveals hair cell–like cells that stain positively for hair cell–specific markers such as myosin VI and myosin VIIa (65). These cells are slightly reduced in number compared with the heterozygote control, and some cells expressing hair cell markers are observed in the supporting cell layer, suggesting defective cell migration. However, all hair cells in the Pou4f3 mutant mice are devoid of stereocilia. By E18.5, the number of hair cell–like cells reduces in the vestibular system to about 25% and by P4 even less hair cells are left. A rapid loss of the vestibular and spiral ganglia occurs as well, all dying via apoptosis (65).

IV. CONCLUDING REMARKS

The POU-domain family of transcription factors play a role in both X-linked and autosomal dominant human hereditary NSHL. While the discovery of POU3F4 mutations in DFN3 human deafness led to the production of a mouse knockout and a study of this gene in mouse inner ear development, a detailed analysis of Pou4f3 in the mouse preceded and actually facilitated the discovery of the human POU4F3 human mutation. The two genes belong to the same family of transcription factors, but they are expressed in distinct cell types and time points, and their respective a ected structures do not overlap.

The extensive study of the Pou3f4 and Pou4f3 mouse mutants sheds some light on the formation of the inner ear, as well as hair cell di erentiation and survival. Compelling areas of further research include the elucidation of POU3F4 upstream regulatory elements that are compromised in DFN3associated deafness. There is also a need to identify the in vivo targets that take part in the mesenchymal-epithelial and mesenchymal-mesenchymal cross-talk in the formation of the otic capsule and other structures of the inner ear. The specific sequences that drive both Pou3f4 and Pou4f3 expression to the inner ear are yet to be found. Furthermore, the elucidation of the downstream targets for both these transcription factors, crucial for inner ear development and hair cell survival, is a key step in understanding the molecular basis of POU-domain transcription factor-associated hearing loss. With the publication of the human, mouse, and other genome sequences, as well as the development of tools for rapid characterization of global gene expression [such as microarrays (66)], these specific questions, crucial for understanding the biology and development of the inner ear, are more likely to be answered. All of these elements will aid in the development of potential remedies both for congenital deafness and for age-related hearing loss (presbycusis) a ecting the majority of the elderly population.

ACKNOWLEDGMENTS

We wish to thank the many scientists who have contributed to work described in this chapter. We would like to thank E. Bryan Crenshaw III, Menging Xiang, and Nathan Fischel-Ghodsian for comments and figures. Research in our laboratory is supported by the European Commission (QLG2-1999- 00988), the NIH/Fogarty International Center (Grant 1 R03 TW01108-01), the F.I.R.S.T. Foundation of the Israel Academy of Sciences and Humanities, the Israel Ministry of Science, Culture, and Sport, and the Israel Ministry of Health.

REFERENCES

1.Veenstra GJ, van der Vliet PC, Destree OH. POU domain transcription factors in embryonic development. Mol Biol Rep 1997; 24:139–155.

2.Andersen B, Rosenfeld MG. POU domain factors in the neuroendocrine system: lessons from developmental biology provide insights into human disease. Endocr Rev 2001; 22:2–35.

3.Latchman DS. POU family transcription factors in the nervous system. J Cell Physiol 1999; 179:126–133.

4.Lander ES, Linton LM, Birren B, et al. Initial sequencing and analysis of the human genome. Nature 2001; 409:860–921.

5.Semenza G.Transcription Factors and Human Disease. New York: Oxford University Press, 1998.

6.Tachibana M. A cascade of genes related to Waardenburg syndrome. J Invest Dermatol Symp Proc 1999; 4:126–129.

7.Shah KN, Dalal SJ, Desai MP, Sheth PN, Joshi NC, Ambani LM. White forelock, pigmentary disorder of irides, and long segment Hirschsprung disease: possible variant of Waardenburg syndrome. J Pediatr 1981; 99:432–435.

8.Bondurand N, Girard M, Pingault V, Lemort N, Dubourg O, Goossens M. Human connexin 32, a gap junction protein altered in the X-linked form of Char- cot-Marie-Tooth disease, is directly regulated by the transcription factor SOX10. Hum Mol Genet 2001; 10:2783–2795.

9.Tassabehji M, Read AP, Newton VE, Harris R, Balling R, Gruss P, Strachan T. Waardenburg’s syndrome patients have mutations in the human homologue of the Pax-3 paired box gene. Nature 1992; 355:635–636.

10.Tassabehji M, Newton VE, Read AP. Waardenburg syndrome type 2 caused by mutations in the human microphthalmia (MITF) gene. Nat Genet 1994; 8:251– 255.

11.Fekete DM, Wu DK. Revisiting cell fate specification in the inner ear. Curr Opin Neurobiol 2002; 12:35–42.

12.Ma Q, Anderson DJ, Fritzsch B. Neurogenin 1 null mutant ears develop fewer,

morphologically normal hair cell in smaller sensory epithelia devoid of innevation. J Assoc Res Otolaryngol 2000; 1:129–143.

13.Liu M, Pereira FA, Price SD, Chu MJ, Shope C, Himes D, Eatock RA, Brownell WE, Lysakowski A, Tsai MJ. Essential role of BETA2/NeuroD1 in development of the vestibular and auditory systems. Genes Dev 2000; 14:2839–2854.

14.Kim WY, Fritzsch B, Serls A, Bakel LA, Huang EJ, Reichardt LF, Barth DS, Lee JE. NeuroD-null mice are deaf due to a severe loss of the inner ear sensory neurons during development. Development 2001; 128:417–426.

15.Karis A, Pata I, van Doorninck JH, Grosveld F, de Zeeuw CI, de Caprona D, Fritzsch B. Transcription factor GATA-3 alters pathway selection of olivocochlear neurons and a ects morphogenesis of the ear. J Comp Neurol 2001; 429:615–630.

16.Zheng JL, Gao WQ. Overexpression of Math1 induces robust production of extra hair cells in postnatal rat inner ears. Nat Neurosci 2000; 3:580–586.

17.Bermingham NA, Hassan BA, Price SD, Vollrath MA, Ben-Arie N, Eatock RA, Bellen HJ, Lysakowski A, Zoghbi HY. Math1: an essential gene for the generation of inner ear hair cells. Science 1999; 284:1837–1841.

18.Zine A, Aubert A, Qiu J, Therianos S, Guillemot F, Kageyama R, de Ribaupierre F. Hes1 and Hes5 activities are required for the normal development of the hair cells in the mammalian inner ear. J Neurosci 2001; 21:4712–4720.

19.Herr W, Sturm RA, Clerc RG, Corcoran LM, Baltimore D, Sharp PA, Ingraham HA, Rosenfeld MG, Finney M, Ruvkun G, et al. The POU domain: a large conserved region in the mammalian Pit-1, Oct-1, Oct-2, and Caenorhabditis elegans unc-86 gene products. Genes Dev 1988; 2:1513–1516.

20.Finney M, Ruvkun G, Horvitz HR. The C. elegans cell lineage and di erentiation gene unc-86 encodes a protein with a homeodomain and extended similarity to transcription factors. Cell 1988; 55:757–769.

21.Finney M, Ruvkun G. The unc-86 gene product couples cell lineage and cell identity in C. elegans. Cell 1990; 63:895–905.

22.Rosenfeld MG. POU-domain transcription factors: pou-er-ful developmental regulators. Genes Dev 1991; 5:897–907.

23.Phillips K, Luisi B. The virtuoso of versatility: POU proteins that flex to fit. J Mol Biol 2000; 302:1023–1039.

24.Klemm JD, Rould MA, Aurora R, Herr W, Pabo CO. Crystal structure of the Oct-1 POU domain bound to an octamer site: DNA recognition with tethered DNA-binding modules. Cell 1994; 77:21–32.

25.Assa-Munt N, Mortishire-Smith RJ, Aurora R, Herr W, Wright PE. The solution structure of the Oct-1 POU-specific domain reveals a similarity to the bacteriophage lambda repressor DNA-binding domain. Cell 1993; 73:193–205.

26.Verrijzer CP, Alkema MJ, van Weperen WW, Van Leeuwen HC, Strating MJ, van der Vliet PC. The DNA binding specificity of the bipartite POU domain and its subdomains. EMBO J 1992; 11:4993–5003.

27.He X, Treacy MN, Simmons DM, Ingraham HA, Swanson LW, Rosenfeld MG. Expression of a large family of POU-domain regulatory genes in mammalian brain development. Nature 1989; 340:35–41.

28.Mathis JM, Simmons DM, He X, Swanson LW, Rosenfeld MG. Brain 4: a novel mammalian POU domain transcription factor exhibiting restricted brain-specific expression. EMBO J 1992; 11:2551–2561.

29.Johnson WA, Hirsh J. Binding of a Drosophila POU-domain protein to a sequence element regulating gene expression in specific dopaminergic neurons. Nature 1990; 343:467–470.

30.Burglin TR, Finney M, Coulson A, Ruvkun G. Caenorhabditis elegans has scores of homoeobox-containing genes. Nature 1989; 341:239–243.

31.Agarwal VR, Sato SM. XLPOU 1 and XLPOU 2, two novel POU domain genes expressed in the dorsoanterior region of Xenopus embryos. Dev Biol 1991; 147:363–373.

32.Matsuzaki T, Amanuma H, Takeda H. A POU-domain gene of zebrafish, ZFPOU1, specifically expressed in the developing neural tissues. Biochem Biophys Res Commun 1992; 187:1446–1453.

33.Shah D, Aurora D, Lance R, Stuart GW. POU genes in metazoans: homologs in sea anemones, snails, and earthworms. DNA Seq 2000; 11:457–461.

34.Bermingham JR Jr, Scherer SS, O’Connell S, Arroyo E, Kalla KA, Powell FL, Rosenfeld MG. Tst-1/Oct-6/SCIP regulates a unique step in peripheral myelination and is required for normal respiration. Genes Dev 1996; 10:1751–1762.

35.Jaegle M, Mandemakers W, Broos L, Zwart R, Karis A, Visser P, Grosveld F, Meijer D. The POU factor Oct-6 and Schwann cell di erentiation. Science 1996; 273:507–510.

36.Nakai S, Kawano H, Yudate T, Nishi M, Kuno J, Nagata A, Jishage K, Hamada H, Fujii H, Kawamura K, et al. The POU domain transcription factor Brn-2 is required for the determination of specific neuronal lineages in the hypothalamus of the mouse. Genes Dev 1995; 9:3109–3121.

37.McEvilly RJ, de Diaz MO, Schonemann MD, Hooshmand F, Rosenfeld MG. Transcriptional regulation of cortical neuron migration by POU domain factors. Science 2002; 295:1528–1532.

38.Phippard D, Heydemann A, Lechner M, Lu L, Lee D, Kyin T, Crenshaw EB III. Changes in the subcellular localization of the Brn4 gene product precede mesenchymal remodeling of the otic capsule. Hear Res 1998; 120:77–85.

39.Jensen J, Heller RS, Funder-Nielsen T, Pedersen EE, Lindsell C, Weinmaster G, Madsen OD, Serup P. Independent development of pancreatic alphaand beta-cells from neurogenin3-expressing precursors: a role for the notch pathway in repression of premature di erentiation. Diabetes 2000; 49:163–176.

40.de Kok YJ, van der Maarel SM, Bitner-Glindzicz M, Huber I, Monaco AP, Malcolm S, Pembrey ME, Ropers HH, Cremers F.P.. Association between X- linked mixed deafness and mutations in the POU domain gene POU3F4. Science 1995; 267:685–688.

41.Brunner HG, van Bennekom A, Lambermon EM, Oei TL, Cremers WR, Wieringa B, Ropers HH. The gene for X-linked progressive mixed deafness with perilymphatic gusher during stapes surgery (DFN3) is linked to PGK. Hum Genet 1988; 80:337–340.

42.Friedman RA, Bykhovskaya Y, Tu G, Talbot JM, Wilson DF, Parnes LS, Fis-

chel-Ghodsian N. Molecular analysis of the POU3F4 gene in patients with clinical and radiographic evidence of X-linked mixed deafness with perilymphatic gusher. Ann Otol Rhinol Laryngol 1997; 106:320–325.

43.Piussan C, Hanauer A, Dahl N, Mathieu M, Kolski C, Biancalana V, Heyberger S, Strunski V. X-linked progressive mixed deafness: a new microdeletion that involves a more proximal region in Xq21. Am J Hum Genet 1995; 56:224–230.

44.de Kok YJ, Vossenaar ER, Cremers CW, et al. Identification of a hot spot for microdeletions in patients with X-linked deafness type 3 (DFN3) 900 kb proximal to the DFN3 gene POU3F4. Hum Mol Genet 1996; 5:1229–1235.

45.Phelps PD, Reardon W, Pembrey M, Bellman S, Luxom L. X-linked deafness, stapes gushers and a distinctive defect of the inner ear. Neuroradiology 1991; 33:326–330.

46.Phippard D, Lu L, Lee D, Saunders JC, Crenshaw EB III. Targeted mutagenesis of the POU-domain gene Brn4/Pou3f4 causes developmental defects in the inner ear. J Neurosci 1999; 19:5980–5989.

47.Phippard D, Boyd Y, Reed V, Fisher G, Masson WK, Evans EP, Saunders JC, Crenshaw EB III. The sex-linked fidget mutation abolishes Brn4/Pou3f4 gene expression in the embryonic inner ear. Hum Mol Genet 2000; 9:79–85.

48.Minowa O, Ikeda K, Sugitani Y, Oshima T, Nakai S, Katori Y, Suzuki M, Furukawa M, Kawase T, Zheng Y, Ogura M, Asada Y, Watanabe K, Yamanaka H, Gotoh S, Nishi-Takeshima M, Sugimoto T, Kikuchi T, Takasaka T, Noda T. Altered cochlear fibrocytes in a mouse model of DFN3 nonsyndromic deafness. Science 1999; 285:1408–1411.

49.Spicer SS, Schulte BA. The fine structure of spiral ligament cells relates to ion return to the stria and varies with place-frequency. Hearing Res 1996; 100:80– 100.

50.Finney M, Ruvkun G. The unc-86 gene product couples cell lineage and cell identity in C. elegans. Cell 1990; 63:895–905.

51.Hutcheson DA, Vetter ML. The bHLH factors Xath5 and XNeuroD can upregulate the expression of XBrn3d, a POU-homeodomain transcription factor. Dev Biol 2001; 232:327–338.

52.Sampath K, Stuart GW. Developmental expression of class III and IV POU domain genes in the zebrafish. Biochem Biophys Res Commun 1996; 219:565– 571.

53.Gruber CA, Rhee JM, Gleiberman A, Turner EE. POU domain factors of the Brn-3 class recognize functional DNA elements which are distinctive, symmetrical, and highly conserved in evolution. Mol Cell Biol 1997; 17:2391–2400.

54.Wang SW, Mu X, Bowers WJ, Kim DS, Plas DJ, Crair MC, Federo HJ, Gan L, Klein WH. Brn3b/Brn3c double knockout mice reveal an unsuspected role for Brn3c in retinal ganglion cell axon outgrowth. Development 2002; 129:467– 477.

55.McEvilly RJ, Erkman L, Luo L, Sawchenko PE, Ryan AF, Rosenfeld MG. Requirement for Brn-3.0 in di erentiation and survival of sensory and motor neurons. Nature 1996; 384:574–577.

56.Xiang M, Gan L, Zhou L, Klein WH, Nathans J. Targeted deletion of the mouse

POU domain gene Brn-3a causes selective loss of neurons in the brainstem and trigeminal ganglion, uncoordinated limb movement, and impaired suckling. Proc Natl Acad Sci USA 1996; 93:11950–11955.

57.Huang EJ, Liu W, Fritzsch B, Bianchi LM, Reichardt LF, Xiang M. Brn3a is a transcriptional regulator of soma size, target field innervation and axon pathfinding of inner ear sensory neurons. Development 2001; 128:2421–2432.

58.Erkman L, McEvilly RJ, Luo L, Ryan AK, Hooshmand F, O’Connell SM, Keithley EM, Rapaport DH, Ryan AF, Rosenfeld MG. Role of transcription factors Brn-3.1 and Brn-3.2 in auditory and visual system development. Nature 1996; 381:603–606.

59.Gan L, Xiang M, Zhou L, Wagner DS, Klein WH, Nathans J. POU domain factor Brn-3b is required for the development of a large set of retinal ganglion cells. Proc Natl Acad Sci USA 1996; 93:3920–3925.

60.Liu W, Khare SL, Liang X, Peters MA, Liu X, Cepko CL, Xiang M. All Brn3 genes can promote retinal ganglion cell di erentiation in the chick. Development 2000; 127:3237–3247.

61.Vahava O, Morell R, Lynch ED, Weiss S, Kagan ME, Ahituv N, Morrow JE, Lee MK, Skvorak AB, Morton CC, Blumenfeld A, Frydman M, Friedman TB, King M-C, Avraham KB. Mutation in transcription factor POU4F3 associated with inherited progressive hearing loss in humans. Science 1998; 279:1950– 1954.

62.Lynch E, Lee MK, Morrow JE, Welcsh PL, Leon PE, MC K. Nonsyndromic deafness DFNA1 associated with mutation of a human homolog of the Drosophila gene diaphanous. Science 1997; 278:1315–1318.

63.Xiang M, Gan L, Li D, Chen ZY, Zhou L, O’Malley BW Jr, Klein W, Nathans J. J. Essential role of POU-domain factor Brn-3c in auditory and vestibular hair cell development. Proc Natl Acad Sci USA 1997; 94:9445–9450.

64.Gottfried I, Huygen PLM, Avraham KB. The clinical presentation of DFNA15/ POU4F3. In: Smith RJH, Cremers CWRJ, eds. Advances in ORL. Basel: Karger AG, 2002, pp. 92–97.

65.Xiang M, Gao WQ, Hasson T, Shin JJ. Requirement for Brn-3c in maturation and survival, but not in fate determination of inner ear hair cells. Development 1998; 125:3935–3946.

66.Schulze A, Downward J. Navigating gene expression using microarrays—a technology review. Nat Cell Biol 2001; 3:E190–E195.

67.Purves WK, Sadava D, Orians GH, Heller HC. Life: The Science of Biology. 6th ed. Massachusets: Sinauer Associates, Inc., 2001.

68.Verrijzer CP, Van der Vliet PC. POU domain transcription factors. Biochim Biophys Acta 1993; 1173:1–21.

69.International Organization for Standardization International Standard ISO 7029, 1984.

ment types (Fig. 1a). These filaments have a diameter that ranges from 7 to 9 nm, are aligned parallel to one another, and are linked together by staggered cross-bridges. The alternating arrangement of the lightand darkstaining filaments gives a striated appearance to the sheets that they form. The available evidence indicates that the striated-sheet matrix is predominantly a tectorin-based structure. It is not degraded by bacterial collagenase (Fig. 1b), it is trypsin sensitive, and its structure is una ected in otogelin null mutant mice (5,6).

III.TECTORINS AS MAJOR NONCOLLAGENOUS COMPONENTS OF THE TECTORIAL MEMBRANE

The tectorins are pepsin-sensitive glycoproteins of the mammalian and avian tectorial membranes that are resistant to digestion with bacterial collagenase (7–9). Mouse a-tectorin is a large disulfide cross-linked complex that barely enters a 8.2% acrylamide resolving gel under nonreducing conditions (Fig. 2a). Following reduction, mouse a-tectorin generates three broad, polydisperse bands with peak apparent molecular masses (Mr) of 173,000, 60,000, and 45,000 (Fig. 2b). These have been referred to as the high-, medium-, and low-molecular-mass mouse tectorins (HMM, MMM, and LMM tectorins) (9). Chick a-tectorin resolves as a discrete band with an Mr of 196,000 under nonreducing conditions (Fig. 2c). On reduction, chick h-tectorin generates six polypeptides (a1–a6) with Mr ranging from 146,000 to 33,000. Beta-tectorin is not covalently associated with a-tectorin and has an Mr of approximately 43,000 under nonreducing conditions in both mouse and chick (Fig. 2a,c). On reduction, h-tectorin shows a small decrease in electrophoretic mobility characteristic of the presence of intrachain disulfide bonds.

Under reducing conditions, mouse h-tectorin comigrates with the LMM tectorin derived from mouse a-tectorin, and chick h-tectorin comigrates with the chick a4-tectorin subunit (Fig. 2b,d). The tectorins react with the lectins from Concanavalia ensiformis and Triticum vulgaris, indicating the presence of mannose and N-acetylglucosamine (7). HMM mouse tectorin also reacts with lectin from Glycine max, indicating the presence of N-acetyl-galactosamine (7), can be metabolically labeled with radioactive sulfate (9), and undergoes a significant shift in electrophoretic mobility following treatment with endo-h- galactosidase (7,9), indicating it may be a sulfated glycoprotein or a keratan sulfate proteoglycan. HMM mouse tectorin has a buoyant density on cesium chloride gradients that is typical of glycoproteins (9), and if it were a proteoglycan it would be classified as a ‘‘light’’ proteoglycan (i.e., has relatively few or only short keratan sulfate GAG associated with it).