A strain-specific modifier on mouse chromosome 4 controls the methylation of independent transgene loci.
A transgene, pHRD, is highly methylated in 12 independent mouse lines when in a C57BL/6 strain background, but becomes progressively less methylated when bred into a DBA/2 background. Transgenes inherited from the mother are generally more methylated; however, this parental effect disappears following continued breeding into the nonmethylating strain. Mapping experiments using BXD recombinant inbred mice as well as other inbred strains indicate that a single strain-specific modifier (Ssm-1) linked to, but distinct from, Fv-1 is responsible for the strain effect. In addition to the methylated and unmethylated transgenic phenotypes, certain mice exhibit a partial methylation pattern that is a consequence of an unusual cellular mosaicism. The pHRD transgene, containing target sequences for the V(D)J recombinase, undergoes site-specific recombination only in lymphoid tissues. This V-J joining is restricted primarily to unmethylated transgene copies.
Engler
P
P
Department of Molecular Genetics and Cell Biology, University of Chicago.
Haasch
D
D
Pinkert
C A
CA
Doglio
L
L
Glymour
M
M
Brinster
R
R
Storb
U
U
D000818:Animals; D002843:Chromatin / Q000648:ultrastructure; D002874:Chromosome Mapping; D004247:DNA / Q000378:metabolism*; D015321:Gene Rearrangement; D008745:Methylation; D051379:Mice; D008810:Mice, Inbred C57BL / Q000235:genetics*; D008822:Mice, Transgenic; D009030:Mosaicism; D010375:Pedigree
D002843:Chromatin; D004247:DNA