title: Functional Role of γ-Crystallin N in the Auditory Hindbrain.
abstract: γ-crystallins are major components of the vertebrate lens but show expression in other tissues as well. Their extralenticular functions remain so far unclear. Here, we explored such roles in the rodent superior olivary complex in which previous analysis demonstrated developmentally regulated expression of Crygd, Cryge and Crygn. Immunohistochemistry with novel antibodies against Crygd/e and Crygn indicate that expression of Crygd/e was moderate and varied between the perinatal superior olivary complex of mice, rats, and gerbils. Crygn-immunoreactivity was more robust and consistently highest in the medial nucleus of the trapezoid body, but also present in other nuclei of the superior olivary complex. To analyze the function of Crygn in the auditory hindbrain, we used a Crygn allele with a floxed exon 2. Upon pairing with Egr2::Cre mice, exon 2, encoding the first two greek key motifs of Crygn, was deleted in the developing auditory hindbrain. Anatomical analysis of these mice revealed a 20% volume reduction in the medial nucleus of the trapezoid body and a 7% reduction in the lateral superior olive at postnatal day 25. This was due to cell loss between postnatal days 4 and 25, whereas cell size was unaffected. Auditory brainstem responses showed normal threshold but a significant increase in the amplitude of wave IV. Crygn is hence required for postmigratory survival and proper function of auditory hindbrain neurons. These results ascertain for the first time an essential extralenticular role for γ-crystallins in vivo.
authors: Neurogenetics group, Center of Excellence Hearing4All, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, 26111, Oldenburg, Germany.
authors: Heiner
authors: H
authors: Hartwich
authors: Neurogenetics group, Center of Excellence Hearing4All, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, 26111, Oldenburg, Germany.
authors: Elena
authors: E
authors: Rosengauer
authors: University of Tübingen, Department of Otolaryngology, Hearing Research Centre Tübingen (THRC), Molecular Physiology of Hearing, Elfriede Aulhorn Str. 5, 72076, Tübingen, Germany.
authors: Lukas
authors: L
authors: Rüttiger
authors: Neurogenetics group, Center of Excellence Hearing4All, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, 26111, Oldenburg, Germany.
authors: Viviane
authors: V
authors: Wilms
authors: Neurogenetics group, Center of Excellence Hearing4All, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, 26111, Oldenburg, Germany.
authors: Sarah-Kristin
authors: SK
authors: Waterholter
authors: Neurogenetics group, Center of Excellence Hearing4All, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, 26111, Oldenburg, Germany.|Research Center for Neurosensory Science, Carl von Ossietzky University Oldenburg, 26111, Oldenburg, Germany.
authors: Hans Gerd
authors: HG
authors: Nothwang
mesh_terms: D000818:Animals; D051767:Early Growth Response Protein 2 / Q000502:physiology*; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D005260:Female; D005849:Gerbillinae; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D012249:Rhombencephalon / Q000166:cytology / Q000378:metabolism*; D038222:gamma-Crystallins / Q000502:physiology*
chemical_list: D051767:Early Growth Response Protein 2; C497327:Egr2 protein, mouse; D038222:gamma-Crystallins