Gfi1 was first identified as causing interleukin 2-independent growth in T cells and lymphomagenesis in mice. Much work has shown that Gfi1 and Gfi1b, a second mouse homolog, play pivotal roles in blood cell lineage differentiation. However, neither Gfi1 nor Gfi1b has been implicated in nervous system development, even though their invertebrate homologues, senseless in Drosophila and pag-3 in C...

Townes-Brocks syndrome (TBS) is an autosomal dominant disorder with multiple malformations and variable expression. Major findings include external ear anomalies, hearing loss, preaxial polydactyly and triphalangeal thumbs, imperforate anus, and renal malformations. Most patients with Townes-Brocks syndrome have normal intelligence, although mental retardation has been noted in a few. (J Med Ge...

Hereditary malformations of the external ear, such as microtia and auditory meatal atresia, unassociated with other congenital defects or syndromes, are rarely reported in the medical literature. McKenzie (1958) described such deformities of the external ear as one of the phenotypic variations within the category of a 'first arch syndrome' caused by a dominant gene with variable pentrance. Comp...

MicroRNAs (miRNAs) are small non-coding RNAs that function through the RNA interference (RNAi) pathway and post-transcriptionally regulate gene expression in eukaryotic organisms. While miRNAs are known to affect cellular proliferation, differentiation, and morphological development, neither their expression nor roles in mammalian inner ear development have been characterized. We have investiga...

Neurosensory epithelia in the inner ear are the crucial structures for hearing and balance functions. Therefore, it is important to understand the cellular and molecular features of the epithelia, which are mainly composed of two types of cells: hair cells (HCs) and supporting cells (SCs). Here we choose to study the inner ear sensory epithelia in adult zebrafish not only because the epithelial...

A forward genetic screen of N-ethyl-N-nitrosourea mutagenized Xenopus tropicalis has identified an inner ear mutant named eclipse (ecl). Mutants developed enlarged otic vesicles and various defects of otoconia development; they also showed abnormal circular and inverted swimming patterns. Positional cloning identified specificity protein 8 (sp8), which was previously found to regulate limb and ...

Townes-Brocks syndrome (TBS) is an autosomal dominant disorder with multiple malformations and variable expression. Major findings include external ear anomalies, hearing loss, limb deformity, imperforate anus, and renal malformations. Hypothyroidism is not a recognized feature of TBS. We are reporting a case of TBS with hypothyroidism, a rare association.

The positional cues for formation of individual inner ear components are dependent on pre-established axial information conferred by inductive signals from tissues surrounding the developing inner ear. This review summarizes some of the known molecular pathways involved in establishing the three axes of the inner ear, anterior-posterior (AP), dorsal-ventral (DV) and medial-lateral (ML). Signals...

To analyze the fundamental role of gap junctions in the vertebrate inner ear, we examined molecular and functional characteristics of gap junctional communication (GJC) in the auditory and vestibular system of the chicken. By screening inner ear tissues for connexin isoforms using degenerate reverse transcription-PCR, we identified, in addition to chicken Cx43 (cCx43) and the inner-ear-specific...

Mammalian inner ear harbors diverse cell types that are essential for hearing and balance. Adenovirus is one of the major vectors to deliver genes into the inner ear for functional studies and hair cell regeneration. To identify adenovirus vectors that target specific cell subtypes in the inner ear, we studied three adenovirus vectors, carrying a reporter gene encoding green fluorescent protein...