Maize Genetics Cooperation

Berkeley, California

U.C. Berkeley

Mu killer locus available in multiple inbred backgrounds.

--Damon Lisch and Richard K. Slotkin

Mu killer is a dominant locus that can silence the Mutator system of transposons heritably and reliably. Lines carrying Mu-tagged alleles can be crossed to lines homozygous for Mu killer resulting in a rapid loss of activity. Subsequent backcrosses to low-copy Mu lines (such as commonly used inbreds) result in a rapid reduction in the number of Mu elements, making isolation of a linked Mu insertions much easier. The loss of activity can also make PCR-based efforts to isolate insertions considerably easier, as somatic Mu activity is eliminated. By crossing a given Mu-induced mutation to both Mu killer and a related line without Mu killer, it is also possible to rapidly test for the possibility that a given mutation is suppressible. In response to requests by cooperators, we have now introgressed Mu killer into five commonly used inbred backgrounds: Mo177, A188, W22, W23 and B73. In each case, the Mu killer locus was introgressed five times into each inbred background and then selfed twice to produced Mu killer homozygotes. These lines will be available in the spring of 2007, when they will be deposited at the Maize Genetics COOP Stock Center (http://maizecoop.cropsci.uiuc.edu/). We also have available homozygous Mu killer lines that carry the bz-mum9 or the a1-mum2 reporter alleles, as well as low copy, or minimal Mutator lines that carry a single MuDR element and a single Mu1 element. Further information is available at our web sites: http://plantbio.berkeley.edu/~mukiller/ and http://plantbio.berkeley.edu/~mukiller/mutator/Mutator%20Home.html. Seed requests can be sent directly to Damon Lisch (dlisch@berkeley.edu) or to the Maize Stock Center.