DNA sequence analysis of Prinker-modified restriction fragments after collection from capillary electrophoresis with replaceable matrices.

This paper demonstrates the procedure of sequencing DNA restriction fragments isolated by a recently developed fraction collector after CE separation. In particular, using pBr 322 plasmid as a model system, a double digest was performed with Eco RI and Pst 1 restriction enzymes to produce two fragments of 749 base pairs (bp) and 3612 bp, both with cohesive ends. Prinkers, specific linkers complementary to the cohesive ends, were then ligated to both fragments (increasing the size by 59 bp each). These Prinker-modified fragments were separated by CE and collected. The success of the collection was demonstrated by reinjection of each isolated fraction with laser-induced fluorescence detection, using ethidium bromide as intercalater. The 808 bp isolated fragment was then polymerase chain reaction-amplified with appropriate primers for the Prinker ends, followed by cycle sequencing. Both strands of the fragment were run on an ABI 373, sequencing 427 bases and 450 bases, respectively, with a read accuracy of 99.3%. This approach with Prinker-modified restriction fragment and automated CE fraction collection can be used as a general procedure for sequencing unknown genomic DNA as well as mutated DNA mixtures.