B6.129-Opn1mw^{tm1(OPN1LW)Nat}/J

Stock number: 008619
Research areas: Sensorineural Research

Description

A portion of the X-linked mouse opsin 1 (medium-wave-sensitive) "green pigment" gene was replaced by a human opsin 1 (long-wave-sensitive) "red pigment" cDNA in these targeted mutant mice. Heterozyguous female mice are endowed with a unique ability to make chromatic discriminations at long wavelengths. Hemizygous males and homozygous females have greater sensitivity to long wavelength light than normal mice.

Detailed description

A portion of the X-linked mouse opsin 1 (medium-wave-sensitive) "green pigment" gene was replaced by a human opsin 1 (long-wave-sensitive) "red pigment" cDNA in these targeted mutant mice. Heterozyguous female mice are endowed with a unique ability to make chromatic discriminations at long wavelengths. Hemizygous males and homozygous females have greater sensitivity to long wavelength light than normal mice. Heterozygotes, hemizygotes, and homozygotes are normal in size, viability, and fertility. Expression is observed in retinal cone photoreceptors as determined by immunostaining. The knocked-in coding sequences are expressed normally.

Development

The 3' portion of exon 2, and exons 3-5 of the x-linked mouse opsin 1 (medium-wave-sensitive) "green pigment" gene were replaced by a human opsin 1 (long-wave-sensitive) "red pigment" cDNA. The targeted mutation was introduced using a 129-derived embryonic stem (ES) cell line and backcrossed 6 times to C57BL/6 (see SNP note below) by the donating laboratory.

A 32 SNP (single nucleotide polymorphism) panel analysis, with 27 markers covering all 19 chromosomes and the X chromosome, as well as 5 markers that distinguish between the C57BL/6J and C57BL/6N substrains, was performed on the rederived living colony at The Jackson Laboratory Repository. While the 27 markers throughout the genome suggested a C57BL/6 genetic background, 2 of 5 markers that determine C57BL/6J from C57BL/6N were found to be segregating. These data suggest the mice sent to The Jackson Laboratory Repository were on a C57BL/6N genetic background.

Allele

Symbol: Opn1mw^{tm1(OPN1LW)Nat}
Name: targeted mutation 1, Jeremy Nathans
MGI accession ID: MGI:2678763
Generation method: Targeted
Attributes: Inserted expressed sequence; Humanized sequence
Marker symbol: Opn1mw
Marker name: opsin 1 (cone pigments), medium-wave-sensitive (color blindness, deutan)
Chromosome: X
Strain of origin: 129
Expressed genes: OPN1LW,opsin 1, long wave sensitive,human
Molecular note: Human cDNA encoding OPN1LW was inserted at the endogenous mouse Opn1mw locus, replacing a 3' portion of exon 2 and all of exons 3, 4, and 5. The allele putatively produces a hybrid protein consisting of 92 N-terminal residues encoded by mouse exon 1 and the 5' portion of exon 2, and 266 C-terminal residues encoded by the human cDNA. Nearly the entire chromophore binding pocket, as well as the residues that account for the difference in absorbance spectra between human and mouse, is derived from the human sequence. Immunostaining indicated expression of the hybrid protein and electroretinogram indicated that the spectral sensitivity of cones containing the targeted allele was similar to that of human red cones.