Rapid Restriction Mapping of Cosmids by Sequence-Specific Triple-Helix-Mediated Affinity Capture
Authors: Ji H.; Francisco T.; Smith L.M.; Guilfoyle R.A.
Source: Genomics, Volume 31, Number 2, January 1996 , pp. 185-192(8)
Publisher: Academic Press
Abstract:
A simple and rapid strategy for restriction mapping based on sequence-specific triple-helix affinity capture (TAC) was developed. The strategy was applied to the analysis of cosmid clones by the construction of a new cosmid vector, ScosTriplex-II, containing two different triple-helix-forming sequences flanking the cloning site of the original SuperCos-1 cosmid vector. For restriction mapping, the recombinant cosmid DNA is digested with Not I restriction enzyme or with one of four intron-encoded endonucleases for excision of intact inserts followed by controlled partial digestion with a mapping enzyme used in conjunction with the corresponding methyltransferase. The partial digestion products are combined with biotinylated triple-helix-forming oligonucleotides to form a triple-helical complex. The triple-helix complexes are immobilized on streptavidin-coated magnetic beads, washed, and eluted with pH 9 buffer solution. The fragments are separated and directly sized by agarose gel electrophoresis. Bidirectional maps are obtained simultaneously by binding to the two different triple-helix-forming oligonucleotides. No probe labeling, gel drying, blotting to membranes, hybridization, or autoradiography is necessary. Also, TAC conditions that permit gel-free isolation of the terminal restriction fragments from cosmid inserts were found. These advantages afforded by ScosTriplex-II should facilitate the automation of cosmid restriction site fingerprinting needed for large-scale mapping and sequencing projects.
Language: English
Document Type: Research article
Affiliations: Department of Chemistry, University of Wisconsin, Madison, Wisconsin, 53706:

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