The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 19, 1995
Filed:
May. 28, 1993
Gordon B Collier, Washington, DC (US);
John F Connaughton, Laytonsville, MD (US);
Jack G Chirikjian, Potomac, MD (US);
Georgetown University, Washington, DC (US);
Abstract
The present invention relates to a method for cloning genes that encode restriction endonucleases by altering the level of a methyl donor co-factor of a DNA methyltransferase that protects the DNA of a host cell from damage by a restriction endonuclease. The method can be used to screen entire DNA libraries en masse to identify clones that encode restriction enzymes by growing one library replicate under high or normal methyl donor conditions to protect host DNA and a second library replicate under low methyl donor conditions allowing DNA damage from the active restriction endonuclease. Clones that encode a restriction enzyme are identified by decreased growth or color produced in response to double stranded DNA damage under the low methyl donor conditions. Colorimetric methods useful in the invention can use SOS-sensitive promoters operably linked to .beta.-galactosidase, which detect DNA damage.