STOCK Hhat^{Tg(TFAP2A-cre)1Will}/J

Stock number: 023407
Product name: AP-2CRE
Strain synonyms: Creface^T
Research areas: Developmental Biology Research, Neurobiology Research, Research Tools

Description

These Creface transgenic mice have a cre-recombinase sequence driven by the human transcription factor AP-2, alpha promoter/enhancer elements, and a polyadenylation sequence followed by parts of exons 5-6 of Tfap2a, encoding the frontonasal prominence (FNP) and limb enhancer elements. This transgene integrated into intron 9 of the hedgehog acyltransferase (Hhat) gene, abolishing Hhat gene function. These mice may be useful for studying craniofacial development.

Detailed description

These Creface transgenic mice express Cre recombinase under the control of the human transcription factor AP-2, alpha (Tfap2a) promoter/enhancer elements. A polyadenylation sequence followed by parts of exons 5-6 of Tfap2a, encoding the frontonasal prominence (FNP) and limb enhancer elements, was inserted downstream of the cre sequence. AP-2alpha is a transcription factor expressed in the neural tube, and in cranial and cardiac neural crest cells in the developing embryo, as well as in the progress zone of the limb bud, the developing kidney, the eye, and surface ectoderm. The transgene was found to have integrated into intron 9 of the hedgehog acyltransferase (Hhat) gene, abolishing Hhat gene function. HHAT deficiency has been associated with holoprosencephaly, failure of the forebrain to bifurcate, together with acrania and agnathia. Hemizygous mice are viable and fertile, while homozygotes are embryonic lethal. These mutants lack Hhat activity resulting in craniofacial development defects evident between E14.5 and E17.5. Homozygous embryos exhibit abnormal morphology of the frontonasal, mandibular, and maxillary processes. They also exhibit defects in the development of the cranium, eye, nasal cavity and septum, mouth, and palates. Neural crest morphology is also altered, as is midbrain and forebrain morphology. Expression of cre recombinase was detected in the embryonic face and limb mesenchyme. When crossed with a strain containing a loxP site-flanked sequence, Cre-mediated recombination results in deletion of the flanked sequence in cre-expressing cells.

For example, when bred to STOCK Tfap2a^tm2Will/J mice (Stock No. 023406) expressing a floxed-Tfap2a gene, frontonasal knockout (FKO) mice exhibit midfacial growth anomalies including shortened snouts and wide-set eyes by postnatal day 15.

Development

The Creface transgene was designed with a cre-recombinase sequence driven by the human transcription factor AP-2, alpha (Tfap2a) promoter/enhancer elements. A polyadenylation sequence followed by parts of exons 5-6 of Tfap2a, encoding the frontonasal prominence (FNP) and limb enhancer elements, was inserted downstream of the cre sequence. The transgene was microinjected into fertilized FVB oocytes and founder mice were bred to FVB mice (See SNP note below). This transgene integrated into intron 9 of the hedgehog acyltransferase (Hhat) gene. Upon arrival at The Jackson Laboratory, transgenic mice were bred to FVB/NJ inbred mice (Stock No. 001800) to establish the colony.

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. Six of the 27 markers throughout the genome were segregating from an unknown source.

Allele

Symbol: Hhat^{Tg(TFAP2A-cre)1Will}
Name: transgene insertion 1, Trevor Williams
MGI accession ID: MGI:3038358
Generation method: Transgenic
Attributes: Recombinase-expressing; Null/Knockout
Marker symbol: Hhat
Marker name: hedgehog acyltransferase
Chromosome: 1
Strain of origin: Not Specified
Expressed genes: cre,cre recombinase,bacteriophage P1
Site of expression: Expression of cre recombinase was detected in the embryonic face and limb mesenchyme.
Molecular note: This transgenic construct consisted of 200 bp of human TFAP2A (TCFAP2A) promoter sequence (encoding a specific enhancer element) followed by NLS-cre, an SV40 polyA signal, and a 1.8 kb TFAP2A genomic fragment extending from within exon 5 through a portion of exon 6. The human intron 5 sequence includes the frontonasal prominence- and limb-specific enhancer. Expression of cre recombinase was detected in the embryonic face and limb mesenchyme. New research has determined that the transgene inserted into intron 9 of the Hhat locus. This insertion creates a non-functional allele.