title: Construction of DNA recognition sites active in Haemophilus transformation.
abstract: Competent Haemophilus cells recognize and preferentially take up Haemophilus DNA during genetic transformation. This preferential uptake is correlated with the presence on incoming DNA of an 11-base-pair (bp) sequence, 5'-A-A-G-T-G-C-G-G-T-C-A-3'. To prove that this sequence is the recognition site that identifies Haemophilus DNA to the competent cell, we have now constructed a series of plasmids, each of which contains the 11-bp sequence. Using two different assay systems we have tested the ability of fragments from these plasmids to compete with cloned Haemophilus DNA fragments that naturally contain the 11-bp sequence. We find that the addition of the 11-bp sequence to a DNA fragment is necessary and sufficient for preferential uptake of that fragment. However, plasmid DNAs containing this sequence may vary as much as 48-fold in uptake activity, and this variation correlates with the A+T-richness of the DNA flanking the 11-mer.
mesh_terms: D001483:Base Sequence; D004262:DNA Restriction Enzymes / Q000378:metabolism; D004269:DNA, Bacterial / Q000032:analysis* / Q000138:chemical synthesis; D004587:Electrophoresis, Agar Gel; D006193:Haemophilus influenzae / Q000235:genetics*; D010957:Plasmids; D013379:Substrate Specificity; D014169:Transformation, Bacterial
chemical_list: D004269:DNA, Bacterial; D004262:DNA Restriction Enzymes