Figure 8.
Cleavage of T-even phage DNA by endonuclease SegB is not affected by the presence of cytosine modifications. (A) Glycosylated 5-hydroxymethylcytosine DNA of phages T2L and T4B, 5-hydroxymethylcytosine DNA of T4290, and cytosine DNA of T4alc7 were cleaved under the standard conditions with the indicated amount of SegB endonuclease followed by separation of the DNA products by FIGE in a 1% agarose gel. The SegB endonuclease cleavage and FIGE was carried out as described in ‘Materials and Methods’ section. (B) Glycosylated 5-hydroxymethylcytosine DNA of phage T2L was cleaved under the standard conditions with 1 U of SegB endonuclease. DNA products were separated in a native 1% agarose gel followed by Southern analysis with a 32P-labeled probe complimentary to the phage T2L tRNA gene. Position of the probe is shown in (C). (C) DNA fragment used as 32P-labeled probe in the Southern analysis (B) is represented as gray bar. Positions of SegB cleavage sites located within the tRNASer (Ser) and tRNAAsn (Asn) genes relative to site of SmiI (S) are also shown.