This allele generates tri-cistronic expression from the Gucy1b2 locus of the endogenous Gucy1b2 gene, cre recombinase with a nuclear localization signal, and a tauLacZ reporter, each separated from the next by an IRES sequence. This provides cre expression in cells expressing GUCY1B2 and marked by tauLacZ expression.
Peter Mombaerts, Max Planck Research Unit for Neurogenetics
This allele generates tri-cistronic expression from the Gucy1b2 locus of the endogenous Gucy1b2 gene, cre recombinase with a nuclear localization signal, and a tauLacZ reporter, each separated from the next by an IRES sequence. This provides cre expression in cells expressing GUCY1B2 and marks them with tauLacZ expression.
Type B olfactory sensory neurons are located in the Zolfr1507 zone of the main olfactory epithelium, but do not express olfactory receptor genes or Adcy3. They do express Gucy1b2 and both Cnga2 and Trpc2 but in separate cellular domains. CNGA2 localizes to the cilia of type B cells and is essential for their ultrasensitive detection of hydrogen sulfide, whereas TRPC2 and GUCY1B2 are detected in the dendritic knob in type B cells and are both essential to their detection of low oxygen levels. This cre recombinase expressing allele was used to generate mice with a Gucy1b2-driven knockout of Cnga2, which proved that CNGA2 is essential for hydrogen sulfide detection but not oxygen detection by type B cells. This finding was confirmed in mice homozygous for a null allele of Cnga2 (Cnga2tm1Mom) carrying the wildtype reporter allele (Trpc2tm2Mom) to identify type B cells. (Koike et al., 2021.)
Working in 129P2/OlaHsd-derived E14 ES cells, an IRES-nlsCre-IRES-taulacZ-FnF cassette was inserted just downstream of the STOP codon of the endogenous Gucy1b2 coding sequence to generate a tri-cistronic allele expressing wild-type, full-length Gucy1b2, cre recombinase with a nuclear localization signal, and taulacZ followed by an FRT-flanked neomycin resistance cassette. The correctly targeted ES cells were injected into C57BL/6 blastocysts and the resulting chimeras were bred to B6.129S4-Gt(ROSA)26Sortm1(FLP1)Dym/RainJ to excise the neomycin resistance cassette. Mice were bred to homozygosity and sent to The Jackson Laboratory where sperm was cryopreserved from homozygous males. Standard cryo-recovery for this strain uses C57BL/6J oocytes.
|Allele Name||targeted mutation 4.1, Peter Mombaerts|
|Allele Type||Targeted (Recombinase-expressing, Reporter)|
|Gene Symbol and Name||Gucy1b2, guanylate cyclase 1, soluble, beta 2|
|Strain of Origin||129P2/OlaHsd|
|Molecular Note||Sequence encoding an IRES followed by Cre recombinase with a nuclear localization signal followed by a second IRES and tau-lacZ followed by an FRT-flanked neomycin selection cassette was inserted immediately downstream of the stop codon, leaving the coding sequence intact with tri-cistronic expression resulting in the co-expression of nuclear-localized cre and the tau-lacZ reporter. Flp-mediated excision removed the neomycin selection cassette.|