Cell 11: 371-81 (1977)[77244007]
The sequence organization of the 1 .688 satellite DNA (density 1.688
g/cm3 in CsCl) has been investigated, and this satellite has been
found to differ from the other 0. melanogaster satellite DNAs in
having a much greater sequence complexity. Purification of 1.688
satellite DNA by successive equilibrium density centrifugations
yielded a fraction 77% pure. Segments of satellite DNA were isolated
by molecular cloning in the plasmid vector pSClOl. One recombinant
plasmid contained a segment of i.688 satellite DNA 5.8 kilobase pairs
in size and was stable during propagation in E. coli. recognition
sites for restriction enzymes from Haemophilus aegyptius (Hae III),
Haemophilus influenzae f (Hint) and Arthrobacter luteus (Alu I) were
mapped in the satellite DNA of this hybrid plasmid. The spacing of
Hae III, Hinf and two Alu I sites at regular intervals of about 365
base pairs is strong evidence that the sequence complexity of this
satellite DNA is 365 base pairs. Further evidence comes from the
finding that both gradient-purified and cloned 1.688 satellite DNA
renature with their Hae ill sites in register. The Hae III and Hint
sites in gradient-purified satellite DNA have been shown by Manteuil,
Hamer and Thomas (1975) and Shen, Wiesehahn and Hearst (1978) to be
distributed at intervals of 365 base pairs and Integral multiples
thereof. These investigators proposed that some of the sites in an
otherwise regular array have been randomly inactivated. Cloned
satellite DNA provided a hybridization probe for sensitive studies of
the arrangement of these recognition sites in gradient-purified
satellite DNA. Some regions of satellite DNA were found to contain
many fewer recognition sites than expected from the pro-posed models.
These findings suggest that different regions of 1.688 satellite DNA
may exhibit different arrangements of Hae III and Hinf recognition
sites.
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