Abstract: Methods, employing a nucleotide integrase, for cleaving single-stranded RNA substrates, single-stranded DNA substrates, and double-stranded DNA substrates at specific sites and for inserting a nucleic acid molecule into the cleaved substrate are provided. One method uses a nucleotide integrase to cleave one strand of a double-stranded DNA substrate. The method comprises the steps of: providing an isolated nucleotide integrase comprising a group II intron RNA having two hybridizing sequences for hybridizing with two intron RNA binding sequences on the top strand of the DNA substrate, and a group I-intron encoded protein which binds to a first sequence element of the substrate; and reacting the nucleotide integrase with the double-stranded DNA substrate to permit the nucleotide integrase to cleave the top strand of the DNA substrate and to insert the group II intron RNA into the cleavage site.

Abstract: Methods, employing a nucleotide integrase, for cleaving single-stranded RNA substrates, single-stranded DNA substrates, and double-stranded DNA substrates at specific sites and for inserting a nucleic acid molecule into the cleaved substrate are provided. One method uses a nucleotide integrase to cleave one strand of a double-stranded DNA substrate. The method comprises the steps of: providing an isolated nucleotide integrase comprising a group II intron RNA having two hybridizing sequences for hybridizing with two intron RNA binding sequences on the top strand of the DNA substrate, and a group II-intron encoded protein which binds to a first sequence element of the substrate; and reacting the nucleotide integrase with the double-stranded DNA substrate to permit the nucleotide integrase to cleave the top strand of the DNA substrate and to insert the group II intron RNA into the cleavage site.

Abstract: The present invention provides new methods, employing a nucleotide integrase, for cleaving single-stranded RNA substrates, single-stranded DNA substrates, and double- stranded DNA substrates at specific sites and for inserting a nucleic acid molecule into the cleaved substrate. One method uses a nucleotide integrase to cleave one strand of a double-stranded DNA substrate. The method comprises the steps of: providing a nucleotide integrase comprising a group II intron RNA having two hybridizing sequences that are capable of hybridizing with two intron RNA binding sequences on the one strand of the DNA substrate, and a group II-intron encoded protein which binds to a first sequence element of the substrate; and reacting the nucleotide integrase with the double-stranded DNA substrate under conditions that permit the nucleotide integrase to cleave the one strand of the DNA substrate and to insert the group II intron RNA into the cleavage site.

Abstract: Methods for preparing nucleotide integrases are provided. The nucleotide integrases are prepared by combining in vitro an excised, group II intron RNA, referred to hereinafter as "exogenous RNA", with a group II intron-encoded protein. The exogenous RNA is prepared by in vitro transcription of a DNA molecule which comprises a group II intron sequence. In one embodiment, the group II intron-encoded protein is made by introducing into a host cell a DNA molecule that comprises at least the open reading frame sequence of a group II intron and then expressing the open reading frame sequence in the host cell. The DNA molecule may comprise the open reading frame sequence operably linked to a promoter, preferably an inducible promoter. Thereafter, the cell is fractionated and the protein is recovered and combined in vitro with the exogenous RNA to provide RNP particles having nucleotide integrase activity.