PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 1873986

Each otoconia polymorph has a protein unique to that polymorph.

K G Pote·M D Ross
View original source ↗Export metadata ↓

Abstract

1. Otoconia, contained within the vestibular portion of the inner ear, are mineralized by one of three polymorphs of calcium carbonate. Each otoconial polymorph contains a unique, major protein. 2. The major protein of calcitic otoconia of members of different vertebrate classes, Amphibia (African clawed frog) and Mammalia (rat), have similar molecular weights. 3. The major protein of calcitic rat otoconia and of vateritic otoconia of the gar may be calcium binding proteins. No protein from the other polymorph, aragonite, appear to have this characteristic.

Explore related subjects

Ambystoma mexicanumAnimalsCalcium CarbonateCalcium-Binding ProteinsMaleMicroscopy, Electron, ScanningMolecular WeightNotophthalmus viridescensOtolithic MembranePolymorphism, GeneticProteinsRana pipiensRatsRats, Inbred StrainsSalmonidaeSpecies SpecificityXenopus laevisComparative StudyJournal ArticleResearch Support, U.S. Gov't, Non-P.H.S.

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

K G Pote, M D Ross. 1991. Each otoconia polymorph has a protein unique to that polymorph.. https://doi.org/10.1016/0305-0491(91)90181-c

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2007

Molecular and immunohistochemical analyses of cardiac troponin T during cardiac development in the Mexican axolotl, Ambystoma mexicanum.

The Mexican axolotl, Ambystoma mexicanum, is an excellent animal model for studying heart development because it carries a naturally occurring recessive genetic mutation, designated gene c, for cardiac nonfunction. The double recessive mutants (c/c) fail to form organized myofibrils in the cardiac myoblasts resulting in hearts that fail to beat. Tropomyosin expression patterns have been studied in detail and show dramatically decreased expression in the hearts of homozygous mutant embryos. Because of the direct interaction between tropomyosin and troponin T (TnT), and the crucial functions of TnT in the regulation of striated muscle contraction, we have expanded our studies on this animal model to characterize the expression of the TnT gene in cardiac muscle throughout normal axolotl development as well as in mutant axolotls. In addition, we have succeeded in cloning the full-length cardiac troponin T (cTnT) cDNA from axolotl hearts. Confocal microscopy has shown a substantial, but reduced, expression of TnT protein in the mutant hearts when compared to normal during embryonic development.

Ambystoma mexicanum↗
PubMed2007

Inhibition of Sonic hedgehog signaling leads to posterior digit loss in Ambystoma mexicanum: parallels to natural digit reduction in urodeles.

Molecular mechanisms patterning the tetrapod limb, including anterior-posterior axis determination involving Sonic hedgehog (Shh), have received much attention, particularly in amniotes. Anterior-posterior patterning in urodele amphibians differs radically from that of amniotes in that it shows a pronounced anterior-to-posterior sequence of digit development. In contrast, amniotes develop their digits almost simultaneously with a slight posterior-to-anterior polarity. Here we use cyclopamine, an inhibitor of the Hedgehog signaling pathway, to investigate the role of Shh in anterior-posterior patterning in the urodele limb. Inhibition of Shh signal transduction affects digit number long before their morphological appearance. In accordance with the apparently derived order of digit development in urodeles, exposure reproducibly removes digits in a posterior-to-anterior sequence, the inverse of their developmental sequence. This pattern of digit loss mimics the order of digit loss in natural variation. We suggest that variation in Shh expression and/or signal transmission may explain natural variation in digit number in urodeles.

Ambystoma mexicanum↗
PubMed2006

Differential expression of tropomyosin during segmental heart development in Mexican axolotl.

The Mexican axolotl, Ambystoma mexicanum, serves as an intriguing model to investigate myofibril organization and heart development in vertebrates. The axolotl has a homozygous recessive cardiac lethal gene "c" which causes a failure of ventricular myofibril formation and contraction. However, the conus of the heart beats, and has organized myofibrils. Tropomyosin (TM), an essential component of the thin filament, has three known striated muscle isoforms (TPM1alpha, TPM1kappa, and TPM4alpha) in axolotl hearts. However, it is not known whether there are differential expression patterns of these tropomyosin isoforms in various segments of the heart. Also, it is not understood whether these isoforms contribute to myofibril formation in a segment-specific manner. In this study, we have utilized anti-sense oligonucleotides to separately knockdown post-transcriptional expression of TPM1alpha and TPM4alpha. We then evaluated the organization of myofibrils in the conus and ventricle of normal and cardiac mutant hearts using immunohistochemical techniques. We determined that the TPM1alpha isoform, a product of the TPM1 gene, was essential for myofibrillogenesis in the conus, whereas TPM4alpha, the striated muscle isoform of the TPM4 gene, was essential for myofibrillogenesis in the ventricle. Our results support the segmental theory of vertebrate heart development.

Ambystoma mexicanum↗