B6.129P2(Cg)-Kmt2e^tm1.1Hjf/J

Stock number: 038163
Product name: Mll5-flox

Research areas: Hematological Research, Neurobiology Research, Research Tools

Description

Mll5-flox mice possess loxP sites flanking exons 3-4 (encoding the PHD domain) of the lysine (K)-specific methyltransferase 2E (Kmt2e, also known as Mll5) gene. These floxed mice are useful for tissue specific deletion of Kmt2e when studying Mll5 (Kmt2e) regulation of hematopoietic stem/progenitor cells.

Detailed description

Kmt2e (lysine (K)-specific methyltransferase 2E, or Mll5) encodes a member of the Trithorax/Mll (mixed lineage leukemia) family of epigenetic regulators and contains an N-terminal PHD zinc finger. MLL5 is involved in DNA double strand repair and hematopoiesis. Mutations in Mll5 are associated with autism. Mll5-flox mice possess loxP sites flanking exons 3-4 of the Kmt2e gene. Exons 3-4 encode the PHD and SET domains. Mice that are homozygous for this allele are viable and fertile. When bred to mice that express tissue-specific Cre recombinase, resulting offspring will have exons 3-4 deleted in the cre-expressing tissues resulting in a tissue specific null allele.

When combined with mice carrying a Cre recombinase that is active in most cells and tissues (such as Tg(CMV-cre)1Cgn, Stock No. 006054), mice bred to homozygosity for the Mll5-null allele exhibit some postnatal lethality (40% loss of homozygotes in a heterozygote x heterozygote cross on a C57BL/6 background), male infertility, reduced growth, increased sensitivity to irradiation, and multiple cell cycle defects in a population of short and long term hematopoietic stem cells.

Development

The Mll5-flox targeting vector was designed to insert a loxP-flanked neomycin-polyA cassette upstream of exon 3 and a loxP site downstream of exon 4 of the lysine (K)-specific methyltransferase 2E (Kmt2e) locus on chromosome 5. Exons 3-4 encode the PHD domain. Deletion of exons 3-4 introduces a frameshift downstream of exon 2 scrambling the protein sequence after residue 64 (of 1868 residues). The construct was electroporated into 129P2/OlaHsd-derived E14.1 embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts. Chimeric males were crossed to C57BL/6J females. Mice were then crossed to a strain carrying Tg(rtetR-tetO-cre)40Mhz (MeuCre40) on a congenic C57BL/6 background to delete the loxP-flanked neomycin cassette, leaving loxP sites flanking exons 3 and 4. Thereafter, Neo-deleted offspring were backcrossed for at least 10 generations onto C57BL/6J before the line was maintained by breeding homozygotes. Upon arrival, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes (Stock No. 000664).

Allele

Symbol: Kmt2e^tm1.1Hjf
Name: targeted mutation 1.1, H J Fehling
MGI accession ID: MGI:3835538
Generation method: Targeted
Attributes: Null/Knockout
Marker symbol: Kmt2e
Marker name: lysine (K)-specific methyltransferase 2E
Marker synonyms: 1810033J14Rik; 9530077A04Rik; D230038D11Rik; HDCMC04P; MLL5; NKp44L; ODLURO; SETD5B
Chromosome: 5
Strain of origin: 129P2/OlaHsd
Molecular note: Exons 3 and 4 were removed by germ line, cre mediated. The absence of protein expression was confirmed by western blot analysis on testis and thymus extracts.