The terminus of SV40 DNA replication and transcription contains a sharp sequence-directed curve.

We have examined nucleosome positioning on two DNA segments containing sharp sequence-directed curvatures. A 223 bp DNA from Crithidia fasciculata was cloned into two sites in pBR325 separated by 28%. These sites were found to selectively reconstitute nucleosomes 5- to 7-fold more effectively than the adjoining straight DNA. The terminus of replication and termini of transcription of SV40 DNA are contained within a region of approximately 200 bp centrally located in a 1216 bp fragment. Visualization of this fragment by electron microscopy revealed a sharp curve of approximately 200 degrees in the terminal region. Reconstitution of histone protein with this fragment revealed a 2- to 5-fold higher probability of assembling nucleosomes in the terminal region over the adjacent DNA.