Expression of GATA3 and tenascin in the avian vestibular maculae: normative patterns and changes during sensory regeneration.
Sensory receptors in the vestibular organs of birds can regenerate after ototoxic injury. Notably, this regenerative process leads to the restoration of the correct patterning of hair cell phenotype and afferent innervation within the repaired sensory epithelium. The molecular signals that specify cell phenotype and regulate neuronal guidance during sensory regeneration are not known, but they are likely to be similar to the signals that direct these processes during embryonic development. The present study examined the recovery of hair cell phenotype during regeneration in the avian utricle, a vestibular organ that detects linear acceleration and head orientation. First, we show that Type I hair cells in the avian vestibular maculae are immunoreactive for the extracellular matrix molecule tenascin and that treatment with the ototoxic antibiotic streptomycin results in a nearly complete elimination of tenascin immunoreactivity. Cells that express tenascin begin to recover after about 2 weeks and are then contacted by calyx terminals of vestibular neurons. In addition, our previous work had shown that the zinc finger transcription factor GATA3 is uniquely expressed within the striolar reversal zone of the utricle (Hawkins et al. [2003] Hum Mol Genet 12:1261-1272), and we show here that this regionalized expression of GATA3 is maintained after severe hair cell lesions and after transplantation of the sensory epithelium onto a chemically defined substrate. In contrast, the expression of three other supporting cell markers--alpha- and beta-tectorin and SCA--is reduced following ototoxic injury. These observations suggest that GATA3 expression may maintain positional information in the maculae during sensory regeneration.
Warchol
Mark E
ME
Department of Otolaryngology, Washington University School of Medicine, St. Louis, Missouri 63110, USA. warcholm@ent.wustl.edu
Speck
Judith D
JD
D000818:Animals; D000900:Anti-Bacterial Agents; D015415:Biomarkers / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology; D002645:Chickens; D050990:GATA3 Transcription Factor / Q000378:metabolism*; D018069:Hair Cells, Vestibular / Q000166:cytology / Q000378:metabolism*; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D009410:Nerve Degeneration / Q000139:chemically induced; D009416:Nerve Regeneration / Q000502:physiology*; D010641:Phenotype; D012444:Saccule and Utricle / Q000166:cytology / Q000378:metabolism*; D013307:Streptomycin; D019063:Tenascin / Q000378:metabolism*; D014018:Tissue Distribution
D000900:Anti-Bacterial Agents; D015415:Biomarkers; D050990:GATA3 Transcription Factor; D019063:Tenascin; D013307:Streptomycin