STOCK Actb^tm1Rsin/J

Stock number: 040588
Product name: Actb-MBS
Strain synonyms: Actb^M, Beta-actin MS2
Research areas: Cell Biology Research, Research Tools

Description

Actb-MBS knock-in mice carry a sequence derived from the bacteriophage MS2 genome in the beta actin (Actb) gene. These mice may be useful for studying the mRNA regulation by visualizing single Actb mRNA molecules in real time and over their lifetime in a living organism.

Of note, the donating investigator has also made available their Arc-PBS mice (Stock No. 040727) with similar mRNA reporter tags.

Detailed description

Actb-MBS knock-in mice carry a sequence derived from the bacteriophage MS2 genome in the ubiquitously expressed beta actin (Actb) gene. When transcribed, the RNA immediately folds into a hairpin that forms the MS2 binding site (MBS) for the bacteriophage MS2 capsid protein (MCP). When cells express both a gene of interest carrying the MBS and a fusion of MCP with a fluorescent protein (MCPFP), mRNAs are fluorescently labeled from the moment they are transcribed. Homozygous Actb-MBS mice are viable and fertile, with no overt phenotype detected. These mice may be useful for studying the mRNA regulation by visualizing single Actb mRNA molecules in real time and over their lifetime in a living organism.

Of note, the donating investigator has also made available their Arc-PBS mice (Stock No. 040727) with similar mRNA reporter tags.

Development

The targeting cassette, consisting of a 1.2-kbp cassette containing 24 repeats of the MBS motif and a loxP flanked neomycin resistance cassette, was inserted into the beta actin (Actb) gene 441 bp downstream of the stop codon and after the zip code, a cis-regulatory sequence for mRNA localization. The construct was electroporated into unspecified 129SV-derived embryonic stem (ES) cells, and correctly targeted clones were screened and used for blastocyst injection. Male mice showing 90% chimerism were identified and mated to female mice of unspecified genetic background for germline transmission to produce founder heterozygous offspring, which were intercrossed to generate homozygous mice. The homozygous mice colony is maintained in a mixed genetic background by the donating laboratory. Upon arrival at The Jackson Laboratory, sperm were cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J (Stock No. 000664) oocytes.

Allele

Symbol: Actb^tm1Rsin
Name: targeted mutation 1, Robert H Singer
MGI accession ID: MGI:5438548
Generation method: Targeted
Synonyms: Actb^M; Actb^tm1Itl
Marker symbol: Actb
Marker name: actin, beta
Marker synonyms: Actx; A-X actin-like protein; beta-actin; BKRNS; BNS; BRWS1; CSMH; DDS1; E430023M04Rik; PS1TP5BP1; THC8
Chromosome: 5
Strain of origin: 129S/SvEv
Molecular note: Twenty-four copies of the MS2 binding site (MBS) for the bacteriophage MS2 capsid protein and a floxed neo cassette were introduced into the 3' UTR. The MBS copies increase the signal-to-noise ratio of the mRNA.