These mice are heterozygous for two different alleles of oculocutaneous albinism II (Oca2): Oca2p-d (dark pink-eye) and Oca2p-cp (p-cleft palate, formerly p11H). The compound heterozygotes have a color phenotype intermediate between those of the two homozygotes with eyes lighter at birth than those of Oca2p-d mice, but not as light as those of Oca2p mice, and darken by weaning.Read More +
Mice homozygous for Oca2p-d (dark pink-eye) are born with lightly pigmented eyes, darker than those of Oca2p/Oca2p mice, which darken by weaning and a coat color "considerably darker than that of Oca2p/Oca2p mice, somewhat resembling that of brown [Tyrp1b/Tyrp1b] mice"; both sexes are fertile (Gardner et al. 1977, Lyon et al. 1992). A normal-sized Oca2p transcript is present in eyes of Oca2p-d/Oca2p-d mice (Gardner et al. 1992), and Southern blot analysis revealed no gross alteration of the Oca2p gene (Gardner et al. 1992, Lyon et al. 1992); thus, the molecular nature of the defect is unknown. Most Oca2p-cp (p-cleft palate, formerly p11H) homozygotes die soon after birth with cleft palate; the few that survive to adulthood exhibit significant dilution of coat color with pink eyes, similar in appearance to Oca2p/Oca2p mice. Oca2p-cp/Oca2p-cp mice were reported by Lyon et al. (1992) to be smaller than littermates and to exhibit a somewhat jerky gait, although Phillips (1992) reported their gait as normal. Philips (1992) indicated that Oca2p-cp homozygous males are fertile, but Johnson and Hunt (1975) reported them to be sterile. Female Oca2p-cp homozygotes are fertile, but fail to care for their young (Lyon et al. 1992). Oca2p-cp is a deletion encompassing all except the first exon of the Oca2p gene (Lyon et al. 1992, Gardner et al. 1992, Nakatsu et al. 1993), the genes encoding the alpha-5 and gamma-3 subunits of the gamma-aminobutyric acid type A receptor (Gabra3 and Gabrg3), and the 5' end of the Gabrb3 gene encoding the beta-3 subunit of the same receptor (Nakatsu et al. 1993); the deletion does not affect the Herc2 gene proximal to Oca2p (Lehman et al. 1998). Oca2p-d/Oca2p-cp compound heterozygotes have a color phenotype intermediate between those of the two homozygotes: eyes are "lighter at birth than those of Oca2p-d/Oca2p-d mice (but not as light as those of Oca2p/Oca2p mice) and darken by weaning"; ears and tail are lighter than those of Oca2p-d/Oca2p-d mice, but coat color is indistinguishable. The compound heterozygotes exhibit no behavioral abnormalities and are fertile (Lyon et al. 1992).
Both the Oca2p-d and Oca2p-cp mutations were radiation induced at the Medical Research Council Radiobiology Unit, Harwell, UK, the former by X-irradiation of the fetus and the latter by neutron irradiation of a male mouse, both of strains/stocks of unidentified lineage.
|Allele Name||pink-eyed dilution cleft palate|
|Allele Type||Radiation induced|
|Allele Synonym(s)||p11H; pcp|
|Gene Symbol and Name||Oca2, oculocutaneous albinism II|
|Strain of Origin||Not Specified|
|General Note||This mutation was found in the progeny of a neutron-irradiated male. Most homozygotes die soon after birth with cleft palate, but a few, presumably with unaffected or slightly affected palates, survive to maturity and are fertile. Female fertility is reduced; males have not been tested (J:2108). The pcp mutation has been shown to be a deletion, which disrupts genes for three gamma-aminobutyric acid type A receptors, Gabra5, Gabrb3, and Gabrg3, which are clustered on Chr 7. The human homologs of these receptor genes are closely linked with the genes for Angelman and Prader-Willi syndromes (J:13583).|
Because of the high neonatal lethality of pcpin the homozygous state, this mutation must be maintained heterozygously; keeping it on the pd/pcpcompound heterozygote allows phenotypic identification of all genotypes.
When using the STOCK Oca2p-d/Oca2p-cp/J mouse strain in a publication, please cite the originating article(s) and include JAX stock #001747 in your Materials and Methods section.