Mir143 (microRNA 143) and Mir145 (microRNA 145) are flanked by loxP sites in this targeted mutation strain, enabling the generation of Cre-mediated, tissue-specific knockouts that affect smooth muscle function.
Dr. Tyler Jacks, Massachusetts Institute of Technology
The mir-143~145 cluster on mouse Chromosome 18 encodes two unrelated miRNAs, Mir143 (microRNA 143) and Mir145 (microRNA 145). Germline deletion of the cluster leads to a range of smooth muscle-related phenotypes (including megacolon, vascular defects and male infertility) that occur with high penetrance and progress with aging.
Mir143 and Mir145 are flanked by loxP sites in this targeted mutation strain, thus enabling Cre-mediated recombination and excision of the cluster. In the floxed configuration, miRNA expression is not affected. Homozygotes are viable, fertile, and do not exhibit any overt phenotypes.
LoxP sites were introduced approximately 250 bp 5' of Mir145 and 500 bp 3' of Mir143. A FRT-Neo-FRT cassette was also placed 3' of Mir143, just inside the floxed region. The mutation was created in (C57BL/6 x 129S4/SvJae)F1-derived v6.5 embryonic stem (ES) cells. The neomycin cassette was removed by breeding founders to a C57BL/6 background beta-actin FlpO strain. This strain was made congenic with C57BL/6 using speed congenic methods by the donating laboratory.
|Allele Name||targeted mutation 1.1, Tyler Jacks|
|Allele Type||Targeted (Null/Knockout)|
|Allele Synonym(s)||miR-143/145F; Mir145/Mir143tm1.1Tyj|
|Gene Symbol and Name||Mirc32, microRNA cluster 32, including Mir143 and Mir145a|
|Strain of Origin||(C57BL/6 x 129S4/SvJae)F1|
|Molecular Note||LoxP sites were introduced approximately 250 bp 5' of Mir145 and 500 bp 3' of Mir143. A FRT-Neo-FRT cassette was also placed 3' of Mir143, just inside the floxed region. Flp-mediated recombination removed the neo cassette.|
Homozygous and heterozygous floxed mice are viable and fertile.
When using the B6(129S4)-Mirc32tm1.1Tyj/J mouse strain in a publication, please cite the originating article(s) and include JAX stock #021213 in your Materials and Methods section.