Correlation of chi orientation with transcription indicates a fundamental relationship between recombination and transcription.
Cross-over hot-spot instigator (Chi) sequences (5'-GCTGGTGG-3') are abundant, strand-specific, sequences, which locally increase recombination in Escherichia coli. Located within G-rich 'recombination islands', Chi orientations correlate with the orientations both of DNA replication and of transcription. Consistent with evidence from eukaryotic systems for a fundamental relationship between recombination and transcription, we find for E. coli Chi sequences, and for Haemophilus influenzae Chi-like sequences, that orientations correlate better with transcription than with replication. Complying with Szybalski's transcription direction rule, open reading frames in these prokaryotes have purine-rich mRNA-synonymous DNA strands. Hence, the G-richness of 'recombination islands' may reflect their correspondence with 'transcriptional islands' (genes). Comparison of a natural with the corresponding shuffled sequence, indicates a base order-dependent island unit of approx. 1kb. 1998 Elsevier Science B.V.
Bell
S J
SJ
Department of Biochemistry, Queen's University, Kingston, Ontario, K7L3N6, Canada.
Chow
Y C
YC
Ho
J Y
JY
Forsdyke
D R
DR
D001482:Base Composition; D001483:Base Sequence; D003434:Crossing Over, Genetic / Q000235:genetics*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics*; D006193:Haemophilus influenzae / Q000235:genetics*; D016366:Open Reading Frames / Q000235:genetics; D011995:Recombination, Genetic / Q000235:genetics*; D014158:Transcription, Genetic / Q000235:genetics*
D004269:DNA, Bacterial