In this conditional mutation strain, microRNA mir-181ab2 (Mir181a-2-Mir181b-2; also called Mirc15) is flanked by loxP sites. Cre excision of the floxed region enables tissue/cell-specific knockouts of the genes. Germline deletion reveals that the locus is involved with embryonic stem cell and hematopoietic stem cell self-renewal.
Chang-Zheng (Eric) Chen, Achelois Pharmaceuticals, Inc.
MicroRNAs are an abundant class of small regulatory RNAs that control gene expression at the posttranscriptional level. The miR-181 family of genes (mir-181ab1 (Mir181a-1 - Mir181b-1; also called Mirc14), mir-181ab2 (Mir181a-2 - Mir181b-2; also called Mirc15) and mir-181cd (Mir181c - Mir181d; also called Mirc16)) produce four nearly identical mature miRNAs (miR-181a, miR-181b, miR-181c and miR-181d) from polycistronic transcripts. Mir-181a-2/b-2 is an intrinsic regulator of self-renewal for embryonic and blood stem cells, and its function in self-renewal is independent of mature miRNA expression.
In this conditional mutation strain, mir-181ab2 (Mirc15) is flanked by loxP sites. Cre excision of the floxed region enables tissue/cell-specific knockouts of the genes.
Germline deletion through cre-mediated excision of the floxed region reveals that the locus is involved with embryonic stem cell and hematopoietic stem cell self-renewal. Whereas loss of mir-181ab2 drastically increases the long-term competitive reconstitution potential of hematopoietic stem cells (HSCs), it has no significant effects on T, B, myeloid, or erythroid lineage differentiation. HSCs self-renew at a faster rate than the wild-type competitor HSCs in lethally irradiated recipients with empty stem cell niches.
A loxP-Mir181a-2 - Mir181b-2-FRT-PGK-neomycin-FRT-loxP targeting construct was introduced to CGR8 129P2/OlaHsd-derived embryonic stem cells. The FRT-flanked PGK-neomycin cassette was excised through crosses with a 129S4 background Gt(ROSA)26Sor Flp recombinase strain (see Stock No. 007844). Mice were backcrossed to C57BL/6J for 10 generations by the donating laboratory.
|Allele Name||targeted mutation 1.1, Chang-Zheng Chen|
|Allele Type||Targeted (Conditional ready (e.g. floxed), No functional change)|
|Gene Symbol and Name||Mirc15, microRNA cluster 15, including Mir181a-2 through Mir181b-2|
|Strain of Origin||129P2/OlaHsd|
|Molecular Note||LoxP sites were inserted at least 125 bp upstream and downstream of the cluster. Flp-mediated recombination removed an FRT-flanked neo cassette.|
Homozygotes and heterozygotes are viable and fertile.
When using the B6.129-Mirc15tm1.1Czc/J mouse strain in a publication, please cite the originating article(s) and include JAX stock #025873 in your Materials and Methods section.