Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2000-1-11
pubmed:abstractText
Tyrosinase is a key enzyme involved in the synthesis of melanin in the retinal pigment epithelium (RPE). Mice that are homozygous for the albino allele at the tyrosinase locus have fewer retinal ganglion cells with uncrossed projections at the optic chiasm. To determine the site of the albino gene action we studied the projections of retinal ganglion cells in two types of pigmentation mosaic mice. First, we generated mosaic mice that contain a translocated allele of the wild-type tyrosinase on one X chromosome but that also have the lacZ reporter transgene on the opposite X chromosome. In these lacZ/tyrosinase mice, which are homozygous for the albino allele on chromosome 7, X-inactivation ensures that tyrosinase cannot be functional within 50% of the retinal ganglion cells and that these individual cells can be identified by their expression of the lacZ reporter gene product, beta-galactosidase. The proportion of uncrossed retinal ganglion cells expressing beta-galactosidase was found to be identical to the proportion that did not express it, indicating that the albino mutation associated with axonal behavior at the optic chiasm must affect ganglion cells in a cell-extrinsic manner. Second, to determine whether the RPE is the source of the extrinsic signal, we generated aggregation chimeras between pigmented and albino mice. In these mosaic mice, the extent of the uncrossed projection corresponded with the amount of pigmented cells within the RPE, but did not correspond with the genotypes of neural retinal cells. These studies demonstrate that the albino mutation acts indirectly upon retinal ganglion cells, which in turn respond by making axonal guidance errors at the optic chiasm.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0012-1606
pubmed:author
pubmed:copyrightInfo
Copyright 1999 Academic Press.
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
216
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
41-56
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Extrinsic modulation of retinal ganglion cell projections: analysis of the albino mutation in pigmentation mosaic mice.
pubmed:affiliation
Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, Tennessee, 38105, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't