The transcription factors Pax-6 and X-dll3 influence visual and olfactory system development in Xenopus laevis
type: CreativeWork
description: Pax-6 and X-dll3 are homeobox-containing transcription factors that are expressed in developing anterior neural structures in Xenopus. Characterization of multiple Xenopus Pax-6 cDNAs reveals that they fall into four distinct classes. These classes are defined based on the presence or absence of a 42 base pair sequence in the paired box, and the presence or absence of a 151 base pair sequence located downstream of the homeobox. Transcripts containing the 151 base pair sequence encode a highly conserved form of Pax-6, and are referred to as Xenopus A variants. Transcripts lacking the 151 base pair sequence, producing a change in reading frame that encodes a novel carboxy terminus, are referred to as Xenopus B variants. Xenopus A and B transcripts are produced from an alternate splicing event that occurs in each of at least two Pax-6 genes existing in the Xenopus genome. Both A and B transcripts are expressed in brain and eye tissue. Antibodies generated against unique peptide sequences located in the carboxy-terminal domains of the proteins produced from Xenopus A and B transcripts distinguish expression patterns for the two resulting proteins, and indicate that they are expressed differentially in the developing retina and lens. Five phenotypes result from overexpression of these Pax-6 transcripts: ectopic lens crystallin expression, reduction of endogenous lens tissue, retinas with altered size and morphology, ectopic eye formation, and a reduction of the olfactory placode. Both Xenopus A and Xenopus B can elicit the reduction of both lens and olfactory placodes, and the expansion of retinal tissue, while only Xenopus A can elicit ectopic eye formation and ectopic lens crystallin expression. These studies indicate that overexpression of Pax-6 can produce differential effects on Xenopus eye development, and support a model whereby the concentration of Pax-6 proteins is a critical factor for the development of the Xenopus lens and retina. Overexpression of X-dll3 tra…
abstract: Pax-6 and X-dll3 are homeobox-containing transcription factors that are expressed in developing anterior neural structures in Xenopus. Characterization of multiple Xenopus Pax-6 cDNAs reveals that they fall into four distinct classes. These classes are defined based on the presence or absence of a 42 base pair sequence in the paired box, and the presence or absence of a 151 base pair sequence located downstream of the homeobox. Transcripts containing the 151 base pair sequence encode a highly conserved form of Pax-6, and are referred to as Xenopus A variants. Transcripts lacking the 151 base pair sequence, producing a change in reading frame that encodes a novel carboxy terminus, are referred to as Xenopus B variants. Xenopus A and B transcripts are produced from an alternate splicing event that occurs in each of at least two Pax-6 genes existing in the Xenopus genome. Both A and B transcripts are expressed in brain and eye tissue. Antibodies generated against unique peptide sequences located in the carboxy-terminal domains of the proteins produced from Xenopus A and B transcripts distinguish expression patterns for the two resulting proteins, and indicate that they are expressed differentially in the developing retina and lens. Five phenotypes result from overexpression of these Pax-6 transcripts: ectopic lens crystallin expression, reduction of endogenous lens tissue, retinas with altered size and morphology, ectopic eye formation, and a reduction of the olfactory placode. Both Xenopus A and Xenopus B can elicit the reduction of both lens and olfactory placodes, and the expansion of retinal tissue, while only Xenopus A can elicit ectopic eye formation and ectopic lens crystallin expression. These studies indicate that overexpression of Pax-6 can produce differential effects on Xenopus eye development, and support a model whereby the concentration of Pax-6 proteins is a critical factor for the development of the Xenopus lens and retina. Overexpression of X-dll3 tra…
author: Sander, Brian Mitchell
language: en_US
keywords: Biology, Molecular., Biology, Neuroscience., Biology, Genetics.
date published: 2000
date modified: 2026-07-24T00:56:22Z
provider: University of Arizona
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: The University of Arizona.

PropertyValue
property ID: Handle
value: http://hdl.handle.net/10150/284197