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Cloning and sequencing the HinfI restriction and modification genes
S Chandrasegaran1, K D Lunnen, H O Smith
1Department of Environmental Health Sciences, Johns Hopkins University, School of Hygiene and Public Health, Baltimore, MD 21205.
Gene
|October 30, 1988
Summary
The HinfI restriction enzyme genes, encoding methylase and endonuclease, were cloned and sequenced. This research identified two open reading frames (ORFs) crucial for HinfI enzyme function.
Area of Science:
- Molecular Biology
- Genetics
- Enzymology
Background:
- Restriction enzymes and modification systems are vital tools in molecular biology.
- Understanding the genetic basis of these systems is essential for genetic engineering and DNA analysis.
Purpose of the Study:
- To clone and characterize the genes responsible for HinfI restriction and modification.
- To determine the genetic organization and sequence of the HinfI system.
Main Methods:
- Cloning of HinfI genes into the pBR322 plasmid using PstI restriction.
- Subcloning into a BclI-AvaI fragment for detailed analysis.
- DNA sequencing of the relevant subfragment.
Main Results:
- The HinfI restriction and modification genes were successfully cloned on a 3.9-kb PstI fragment.
- Both genes were localized to a 2.3-kb BclI-AvaI subfragment.
- DNA sequencing revealed two large open reading frames (ORFs): ORF1 for methylase (359 aa) and ORF2 for endonuclease (262 or 272 aa).
Conclusions:
- The HinfI restriction-modification system is encoded by two distinct genes within a specific DNA region.
- The predicted amino acid sequences provide insights into the functional domains of the HinfI methylase and endonuclease.