title: Conditional alleles for activation and inactivation of the mouse Rx homeobox gene.
abstract: The Rx homeobox gene is a transcriptional regulator indispensable for development of the eye and ventral forebrain. Rx-null homozygotes lack optic pits, which are the earliest ocular structures. To study the roles Rx may play at various stages of eye and brain development, we generated an allelic series at the Rx locus. The targeted allele, Rx(neo), is a severely hypomorphic or null allele. This Rx(neo) allele is converted via FLP-mediated recombination to the Rx(flox) allele, which is phenotypically identical to the wildtype allele. Cre-mediated conversion of Rx(flox) generates the RxDelta2 allele, which, when homozygous, results in an Rx-null phenotype that includes perinatal lethality, anophthalmia, and anterior neural and craniofacial defects. Mice carrying these alleles allow both Cre-mediated inactivation and FLP-mediated activation of Rx gene activity on a conditional basis and will be useful in examining Rx function at different developmental stages and in distinct tissue environments.
authors.affiliation: Laboratory of Cancer and Developmental Biology, NCI-Frederick, National Institutes of Health, Frederick, Maryland 21707, USA.
authors.forename: Vera A
authors.initials: VA
authors.lastname: Voronina
authors.forename: Serguei
authors.initials: S
authors.lastname: Kozlov
authors.forename: Peter H
authors.initials: PH
authors.lastname: Mathers
authors.forename: Mark
authors.initials: M
authors.lastname: Lewandoski
mesh_terms: D000483:Alleles; D000818:Animals; D001921:Brain / Q000196:embryology*; D019465:Craniofacial Abnormalities / Q000235:genetics*; D004254:DNA Nucleotidyltransferases / Q000378:metabolism; D005123:Eye / Q000196:embryology*; D005124:Eye Abnormalities / Q000235:genetics; D005136:Eye Proteins / Q000235:genetics* / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D005801:Genes, Homeobox; D018398:Homeodomain Proteins / Q000235:genetics* / Q000502:physiology*; D019426:Integrases / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D010641:Phenotype
chemical_list: D005136:Eye Proteins; D018398:Homeodomain Proteins; C501274:Rx protein, mouse; C045073:Cre recombinase; D004254:DNA Nucleotidyltransferases; C045119:FLP recombinase; D019426:Integrases