Home About us Contact
|
Home About us Contact | ||
|
|
||
Mouse Inner Ear (mouse + inner_ear)
Selected AbstractsDevelopmental Expression of Aquaporin 2 in the Mouse Inner Ear ,THE LARYNGOSCOPE, Issue 11 2000Michele Merves Abstract Objectives The maintenance of endolymph homeostasis is critical for the inner ear to perform its functions of hearing and maintaining balance. The identification and cloning of aquaporins (a family of water channel proteins) has allowed the study of a novel cellular mechanism potentially involved in endolymph homeostasis. The objective of the present study was to define the developmental temporal and spatial e-pression pattern of aquaporin 2 (Aqp2) in the developing mouse inner ear. Study Design A systematic immunohistochemical study of Aqp2 protein e-pression was performed on embryonic mouse inner ears ranging from embryonic day 10 (otocyst stage) to embryonic day 18 (just before birth). Methods Serial cryosections of embryonic mouse inner ears were used for immunohistochemical e-periments. A rabbit polyclonal antisera raised against a synthetic Aqp2 peptide was used with a standard nickel intensified 3,3-diaminobenzidine reaction protocol for immunolocalization of Aqp2 in tissue sections. Results Aquaporin 2 is e-pressed diffusely in the early otocyst, then becomes progressively restricted as the inner ear matures. During early cochlear duct formation (embryonic days 12 and 13), e-pression of Aqp2 is homogeneous; later, it becomes restricted to specific regions of the endolymphatic compartment (embryonic days 15 and 18). Similar restriction of e-pression patterns could be noted for the vestibular structures. Endolymphatic duct and sac and stria vascularis e-pression of Aqp2 was noted to occur fairly late during development but demonstrated a distinct pattern of immunolabeling. Conclusions Aquaporin 2 shows an early and specific pattern of e-pression in the developing mouse inner ear, suggesting a significant role for this water channel protein in the development of endolymph homeostasis and meriting further functional studies of Aqp2 in the inner ear. [source] Diverse expression patterns of LIM-homeodomain transcription factors (LIM-HDs) in mammalian inner ear developmentDEVELOPMENTAL DYNAMICS, Issue 11 2008Mingqian Huang Abstract LIM-homeodomain transcription factors (LIM-HDs) are essential in tissue patterning and differentiation. But their expression patterns in the inner ear are largely unknown. Here we report on a study of twelve LIM-HDs, by their tempo-spatial patterns that imply distinct yet overlapping roles, in the developing mouse inner ear. Expression of Lmx1a and Isl1 begins in the otocyst stage, with Lmx1a exclusively in the non-sensory and Isl1 in the prosensory epithelia. The second wave of expression at E12.5 includes Lhx3, 5, 9, Isl2, and Lmx1b in the differentiating sensory epithelia with cellular specificities. With the exception of Lmx1a and Lhx3, all LIM-HDs are expressed in ganglion neurons. Expression of multiple LIM-HDs within a cell type suggests their redundant function. Developmental Dynamics 237:3305,3312, 2008. © 2008 Wiley-Liss, Inc. [source] Mutations of the RDX gene cause nonsyndromic hearing loss at the DFNB24 locus,,HUMAN MUTATION, Issue 5 2007Shahid Y. Khan Abstract Ezrin, radixin, and moesin are paralogous proteins that make up the ERM family and function as cross-linkers between integral membrane proteins and actin filaments of the cytoskeleton. In the mouse, a null allele of Rdx encoding radixin is associated with hearing loss as a result of the degeneration of inner ear hair cells as well as with hyperbilirubinemia due to hepatocyte dysfunction. Two mutant alleles of RDX [c.1732G>A (p.D578N) and c.1404_1405insG (p.A469fsX487)] segregating in two consanguineous Pakistani families are associated with neurosensory hearing loss. Both of these mutant alleles are predicted to affect the actin-binding motif of radixin. Sequence analysis of RDX in the DNA samples from the original DFNB24 family revealed a c.463C>T transition substitution that is predicted to truncate the protein in the FERM domain (F for 4.1, E for ezrin, R for radixin, and M for moesin) (p.Q155X). We also report a more complete gene and protein structure of RDX, including four additional exons and five new isoforms of RDX that are expressed in human retina and inner ear. Further, high-resolution confocal microscopy in mouse inner ear demonstrates that radixin is expressed along the length of stereocilia of hair cells from both the organ of Corti and the vestibular system. Hum Mutat 28(5), 417,423, 2007. Published 2007 Wiley-Liss, Inc. [source] Molecular characterization and expression of maternally expressed gene 3 (Meg3/Gtl2) RNA in the mouse inner earJOURNAL OF NEUROSCIENCE RESEARCH, Issue 2 2006Shehnaaz S.M. Manji Abstract The pathways responsible for sound perception in the cochlea involve the coordinated and regulated expression of hundreds of genes. By using microarray analysis, we identified several transcripts enriched in the inner ear, including the maternally expressed gene 3 (Meg3/Gtl2), an imprinted noncoding RNA. Real-time PCR analysis demonstrated that Meg3/Gtl2 was highly expressed in the cochlea, brain, and eye. Molecular studies revealed the presence of several Meg3/Gtl2 RNA splice variants in the mouse cochlea, brain, and eye. In situ hybridizations showed intense Meg3/Gtl2 RNA staining in the nuclei of type I spiral ganglion cells and in cerebellum near the dorsal vestibular region of the cochlea. In embryonic mouse head sections, Meg3/Gtl2 RNA expression was observed in the otocyst, brain, eye, cartilage, connective tissue, and muscle. Meg3/Gtl2 RNA expression increased in the developing otocyst and localized to the spiral ganglion, stria vascularis, Reissner's membrane, and greater epithelial ridge (GER) in the cochlear duct. RT-PCR analysis performed on cell lines derived from the organ of Corti, representing neural, supporting, and hair cells, showed significantly elevated levels of Meg3/Gtl2 expression in differentiated neural cells. We propose that Meg3/Gtl2 RNA functions as a noncoding regulatory RNA in the inner ear and that it plays a role in pattern specification and differentiation of cells during otocyst development, as well as in the maintenance of a number of terminally differentiated cochlear cell types. © 2005 Wiley-Liss, Inc. [source] Developmental Expression of Aquaporin 2 in the Mouse Inner Ear ,THE LARYNGOSCOPE, Issue 11 2000Michele Merves Abstract Objectives The maintenance of endolymph homeostasis is critical for the inner ear to perform its functions of hearing and maintaining balance. The identification and cloning of aquaporins (a family of water channel proteins) has allowed the study of a novel cellular mechanism potentially involved in endolymph homeostasis. The objective of the present study was to define the developmental temporal and spatial e-pression pattern of aquaporin 2 (Aqp2) in the developing mouse inner ear. Study Design A systematic immunohistochemical study of Aqp2 protein e-pression was performed on embryonic mouse inner ears ranging from embryonic day 10 (otocyst stage) to embryonic day 18 (just before birth). Methods Serial cryosections of embryonic mouse inner ears were used for immunohistochemical e-periments. A rabbit polyclonal antisera raised against a synthetic Aqp2 peptide was used with a standard nickel intensified 3,3-diaminobenzidine reaction protocol for immunolocalization of Aqp2 in tissue sections. Results Aquaporin 2 is e-pressed diffusely in the early otocyst, then becomes progressively restricted as the inner ear matures. During early cochlear duct formation (embryonic days 12 and 13), e-pression of Aqp2 is homogeneous; later, it becomes restricted to specific regions of the endolymphatic compartment (embryonic days 15 and 18). Similar restriction of e-pression patterns could be noted for the vestibular structures. Endolymphatic duct and sac and stria vascularis e-pression of Aqp2 was noted to occur fairly late during development but demonstrated a distinct pattern of immunolabeling. Conclusions Aquaporin 2 shows an early and specific pattern of e-pression in the developing mouse inner ear, suggesting a significant role for this water channel protein in the development of endolymph homeostasis and meriting further functional studies of Aqp2 in the inner ear. [source] | ||||||||||