Discovery of induced point mutations in maize genes by TILLING.
BACKGROUND
Going from a gene sequence to its function in the context of a whole organism requires a strategy for targeting mutations, referred to as reverse genetics. Reverse genetics is highly desirable in the modern genomics era; however, the most powerful methods are generally restricted to a few model organisms. Previously, we introduced a reverse-genetic strategy with the potential for general applicability to organisms that lack well-developed genetic tools. Our TILLING (Targeting Induced Local Lesions IN Genomes) method uses chemical mutagenesis followed by screening for single-base changes to discover induced mutations that alter protein function. TILLING was shown to be an effective reverse genetic strategy by the establishment of a high-throughput TILLING facility and the delivery of thousands of point mutations in hundreds of Arabidopsis genes to members of the plant biology community.


RESULTS
We demonstrate that high-throughput TILLING is applicable to maize, an important crop plant with a large genome but with limited reverse-genetic resources currently available. We screened pools of DNA samples for mutations in 1-kb segments from 11 different genes, obtaining 17 independent induced mutations from a population of 750 pollen-mutagenized maize plants. One of the genes targeted was the DMT102 chromomethylase gene, for which we obtained an allelic series of three missense mutations that are predicted to be strongly deleterious.


CONCLUSIONS
Our findings indicate that TILLING is a broadly applicable and efficient reverse-genetic strategy. We are establishing a public TILLING service for maize modeled on the existing Arabidopsis TILLING Project.
Till
Bradley J
BJ
Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA. btill@fhcrc.org
Reynolds
Steven H
SH
Weil
Clifford
C
Springer
Nathan
N
Burtner
Chris
C
Young
Kim
K
Bowers
Elisabeth
E
Codomo
Christine A
CA
Enns
Linda C
LC
Odden
Anthony R
AR
Greene
Elizabeth A
EA
Comai
Luca
L
Henikoff
Steven
S
D005020:Ethyl Methanesulfonate / Q000494:pharmacology; D017343:Genes, Plant / Q000235:genetics*; D005820:Genetic Testing / Q000379:methods*; D005838:Genotype; D016296:Mutagenesis / Q000187:drug effects / Q000235:genetics*; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D017354:Point Mutation / Q000235:genetics*; D003313:Zea mays / Q000187:drug effects / Q000235:genetics*
D010940:Plant Proteins; D005020:Ethyl Methanesulfonate