STOCK Tg(Six3-cre)69Frty/GcoJ

Stock number: 019755
Product name: Six3Cre
Strain synonyms: Six3^A1A2-Cre
Research areas: Developmental Biology Research, Neurobiology Research, Research Tools, Sensorineural Research

Description

Six3Cre mice express Cre recombinase in the developing retina and forebrain starting at E9.0.

Detailed description

Six3Cre mice express nuclear localized Cre recombinase under the control of the murine sine oculis-related homeobox 3 (Six3) promoter. Six3 is a transcription factor that is required for the development of the eye. Cre recombinase expression is evident in the retina and the ventral aspect of the optic stalk by E9.0. The entire retina displays cre activity by E12.5. Expression is also seen in the developing ventral forebrain. When crossed with a strain containing a loxP-flanked sequence, Cre-mediated recombination results in deletion of the flanked sequence in the developing eye and ventral forebrain. Homozygotes are viable and fertile.

Luo et al. 2020 Neuron 106:37 Table 1 shows germline recombination in offspring (F2) of Cre;floxed double mutant (F1) mice bred to floxed and/or wildtype mice. The authors also note that in general, the frequency of recombination in Cre;floxed double mutant germline cells appears to be considerably higher than in zygotes produced by breeding Cre mice to floxed mice.
This reports that both female and male Six3-Cre;floxed double mutants bred to floxed mice produced some offspring with germline deletion of the floxed allele [several cohorts, some as high as 100% (12/12 including 4 Cre negative offspring) and 51.9.% (177/341 including 58 Cre negative offspring) when using Cre female or Cre male, respectively]. As such, for Cre-lox experiments and to reduce the frequency of germline deletion of the floxed allele, researchers may consider maintaining the Six3-Cre transgene as hemizygous rather than homozygous and in males instead of females. Researchers are urged to monitor their Cre;floxed double mutant mice for any undesirable germline deletion of the floxed allele (e.g., genotyping tail/ear samples). Researchers may consider also maintaining a Six3-Cre colony separate from any floxed colonies.

If the recombinase activity pattern of this allele is further characterized by the Genetic Resource Science group at The Jackson Laboratory, such findings will be reported on the Mouse Genome Informatics (MGI) Allele Detail entry. This same information may also be found searching the MGI Recombinase Activity and MGI Gene Expression + Recombinase Activity Comparison Matrix.

Development

A transgenic construct containing cre coding sequence, with a nuclear localization signal, under the control of the murine sine oculis-related homeobox 3 (Six3) promoter was introduced into C57BL/6 X DBA2 F2 donor oocytes. Resulting Six3Cre offspring from founder line 69 were bred to and further maintained on an NMRI outbred background. Upon arrival at The Jackson Laboratory, mice were bred to C57BL/6J (Stock No. 000664) for at least one generation to establish the colony.

Allele

Symbol: Tg(Six3-cre)69Frty
Name: transgene insertion 69, Yasuhide Furuta
MGI accession ID: MGI:3574771
Generation method: Transgenic
Attributes: Recombinase-expressing
Marker symbol: Tg(Six3-cre)69Frty
Marker name: transgene insertion 69, Yasuhide Furuta
Chromosome: UN
Strain of origin: (C57BL/6 x DBA/2)F2
Expressed genes: cre,cre recombinase,bacteriophage P1
Site of expression: Cre recombinase is expressed in the developing retina and forebrain.
Molecular note: Cre cDNA with an SV40 NLS and bovine growth hormone pA were placed under the control of the Six3 regulatory sequences by insertion into the first coding exon. This line represents lines 22, 46, and 51.