STOCK Tg(Lmx1a-EGFP/cre)3Kjmi/J

Stock number: 037459
Product name: Lmx1a-Cre
Research areas: Cancer Research, Neurobiology Research, Research Tools

Description

Lmx1a-Cre transgenic mice express a Cre recombinase/EGFP fusion under the control of the mouse Lmx1a (LIM homeobox transcription factor 1 alpha) promoter elements. Please note: the transgene inserted on the X chromosome. Cre recombinase activity is observed specifically in the roof plate (RF) and a subset of rhombic lip (RL) progenitors. This strain may be useful in fate mapping and manipulating gene expression in multiple Lmx1a populations.

Detailed description

Lmx1a (LIM homeobox transcription factor 1 alpha) encodes a transcription factor that contains a homeobox domain. It is expressed in the dorsal midline and roof plate at all axial levels. In the anterior hindbrain, it is expressed in the rhombic lip and in the forebrain, it is expressed in the cortical hem - structures that are adjacent to the roof plate. In the developing cerebellum, Lmx1a is expressed in a subset of rhombic lip derivatives, the ventral midbrain, and in the developing inner ear.  Lmx1a is required for correct fate allocations of multiple dorsal neuronal populations including several cerebellar rhombic lip derivatives.

X-linked Lmx1a-Cre transgenic mice contain a mouse Lmx1a promoter directing EGFP and Cre recombinase expression. EGFP/Cre expression recapitulates Lmx1a expression in the 4^th ventricle roof plate (RP) and choroid plexus, rhombic lip (RL), c3 cells and unipolar brush cells. No GFP expression is observed in deep cerebellar nuclei. There is no ectopic expression of GFP in the cerebellar anlage at any stage. The transgene is also expressed in the cortical hem and lateral ventricle choroid plexus. While roof plate, rhombic lip and cortical hem expression are well recapitulated with the transgene not all endogenous expression of the Lmx1a gene is recapitulated since the entire Lmx1a locus is not present on the transgene. When transgenic mice are bred with mice containing loxP-flanked (floxed) sequences, cre-mediated recombination will result in deletion of floxed sequences in Lmx1a-expressing cells of offspring. Hemizygous mice are viable and fertile with no reported phenotypic abnormalities. Homozygous females are viable and fertile. This strain may be useful in fate mapping and manipulating gene expression in multiple Lmx1a populations.

Development

The bacterial artificial chromosome, RP22-296024, containing the first three exons of the mouse Lmx1a gene was modified by recombineering to target the Lmx1a translation initiation codon with an EGFP/Cre recombinase cassette. The donating investigator has indicated that the BAC also includes the last three exons of the proximal Rxrg gene and all intergenic sequences. The BAC was microinjected into the pronuclei of fertilized outbred CD1 oocytes. The transgene inserted on the X chromosome. Founder line 3 was bred to CD1 mice and maintained on a mixed C57BL/6, CD-1 backgound prior to sending frozen sperm to The Jackson Laboratory in 2023. Upon arrival, the strain was bred to C57BL/6J for at least one generation.

Allele

Symbol: Tg(Lmx1a-EGFP/cre)3Kjmi
Name: transgene insertion 3, Kathleen J Millen
MGI accession ID: MGI:4461311
Generation method: Transgenic
Attributes: Recombinase-expressing
Synonyms: Lmx1a-Cre; Tg(Lmx1a-EGFP/cre)#Kjmi
Marker symbol: Tg(Lmx1a-EGFP/cre)3Kjmi
Marker name: transgene insertion 3, Kathleen J Millen
Marker synonyms: Lmx1a-cre
Chromosome: X
Strain of origin: CD-1
Molecular note: The mouse BAC RP22-296O24 was modified by inserting an EGFP-cre cassette into the translation initiation codon of the Lmx1a locus using BAC recombineering methods. The BAC also includes the last three exons of the proximal Rxrg gene and all intergenic sequences. The transgene inserted on the X chromosome.