B6.FVB-Tg(GNAT2-Dta)98Wwk/J

Stock number: 006576
Product name: h-GNAT2pro-DTA
Research areas: Developmental Biology Research, Research Tools, Sensorineural Research

Description

The transgene in these mice contains a human cone transducin alpha-subunit (GNAT2) promoter, an attenuated diphtheria toxin A (DTA) gene, and an enhancer element from the human interphotoreceptor retinoid-binding protein (IRBP) gene.

Detailed description

Mice hemizygous for this "Trc-Tox176" transgene (also called "h-GNAT2pro-DTA") are viable and fertile. Expression of diphtheria toxin (DTA) from the transgene is similar to that of endogenous GNAT2, leading to ablation of both rod and cone photoreceptor development in the ventral retina (the abnormality is a result of abnormal cellular development rather than a consequence of retinal degeneration). The dorsal retina has nearly normal development of rods, but the development of cones is limited to about 10%. These transgenic mice exhibit an absence of cone photoreceptors in the retina, as well as the concomitant absence of rod photoreceptors in the ventral retina. The mice may be useful in studies of photoreceptor development, photoreceptor-related retinal diseases, and to profile photoreceptor genes in adult and in developmental stages.

Development

A 2.4 kb transgenic construct was designed placing a 277 bp cone photoreceptor cell-specific promoter of human cone transducin alpha-subunit (GNAT2) upstream of a 680 bp attenuated diphtheria toxin A-chain gene (Tox176), and a 214 bp enhancer element from human interphotoreceptor retinoid-binding protein (IRBP) downstream of an SV40 intron and poly A site. This transgene was microinjected into single-cell stage FVB/N embryos. Since FVB/N mice have a recessive mutation at the rd (or Pde6b^rd1) locus, founder line Tg98 mice were bred with C57BL/6J mice to establish stable "Trc-Tox176" transgenic mouse lines. Male transgenic mice were mated with C57BL/6J females for approximately 10 generations prior to arrival at The Jackson Laboratory.

Allele

Symbol: Tg(GNAT2-Dta)98Wwk
Name: transgene insertion 98, Winston W-Y Kao
MGI accession ID: MGI:3693959
Generation method: Transgenic
Attributes: Inserted expressed sequence
Marker symbol: Tg(GNAT2-Dta)98Wwk
Marker name: transgene insertion 98, Winston W-Y Kao
Chromosome: UN
Strain of origin: FVB/N
Expressed genes: Dta,Diphtheria toxin A chain,
Molecular note: The 2.4-kb transgenic construct comprises a 277-base pair (-bp) DNA fragment containing the cone photoreceptor cell-specific promoter from the human GNAT2 gene upstream of a 680-bp cDNA encoding an attenuated diphtheria toxin A-chain followed by an SV40 intron and polyadenylation signal and a 214-bp enhancer element from the human RBP3 gene. While RT-PCR detects transcripts from the endogenous Gnat1 and Gnat2 genes, (encoding the rod and cone transducin alpha subunits, respectively) in wild-type retinas from postnatal day 8 (P8) onward, neither endogenous Gnat2 transcripts nor transgene-derived mRNA are detected in retinas from mice of transgenic line 98 at P8 or later.
General note: Of four transgenic lines derived from independent germline-transmitting transgenic founder mice, only the line descended from male founder C98, estimated by Southern blot analysis to carry approximately 10 tandemly-arrayed copies of the transgene, exhibited a retinal phenotype. Lines derived from female founders C8, C12 and C13, each estimated to carry two tandemly integrated copies of the transgene, exhibited no retinal phenotype even at 180 days of age and so were not characterized further.