We will develop highly specific DNA cleavage tools, based on coupling adenine methylation with the methylation-dependent restriction-endonuclease Dpnl. We have produced DNA fragments of over 1,000,000 base pairs in size with one methylase/Dpnl cleavage system, and separated the resulting pieces by pulsed field gel electrophoresis. These results encourage us to develop the other methylase/Dpnl cleavage specificities based on known restriction modification systems, of which there are at least 22 possible. The cleavage specificities so generated recognize DNA sequences ranging from 8 to 14 base pairs in length and give average fragment sizes of 65,000 (4(8)) to 256,000,000 (4(14)) base pairs on random DNA. We intend to characterize, purify and clone those methylases that have the correct Gm6A specificity for use with Dpnl. This battery of methylase/Dpnl specificities can be applied to three mapping strategies: (1) The production of a physical map of the human genome using restriction fragment length polymorphism probes that have already been ordered genetically. (2) Construction of unique sites in insertion vectors such as retroviruses for the mapping of large portions of the human genome by Smith-Birnstiel indirect end-labelling. (3) Identification of 'linking clones' containing rare cleavage sites for the production of a physical map of these rare sites in the human genome.

Agency
National Institute of Health (NIH)
Institute
National Human Genome Research Institute (NHGRI)
Type
Research Project (R01)
Project #
1R01HG000106-01
Application #
3333130
Study Section
Special Emphasis Panel (SRC)
Project Start
1989-12-15
Project End
1992-11-30
Budget Start
1989-12-15
Budget End
1990-11-30
Support Year
1
Fiscal Year
1990
Total Cost
Indirect Cost
Name
California Institute of Biological Research
Department
Type
DUNS #
City
La Jolla
State
CA
Country
United States
Zip Code
92037
Welsh, J; Chada, K; Dalal, S S et al. (1992) Arbitrarily primed PCR fingerprinting of RNA. Nucleic Acids Res 20:4965-70