Bending of a highly repetitive component in rat nuclear DNA

A highly repetitive component in rat nuclear DNA was isolated by HindIII digestion and cloned. A 370-bp cloned component was highly AT-rich (68.3%) in about one third of the region from the 3'-terminus and showed an anomalously slow gel electrophoretic mobility (k-factor = 1.19). These results indicated that a sequence-directed bending of the helix axis occurs in the component. Accordingly, a subclone containing a tandem dimer of the component was isolated and subjected to a circular permutation analysis for exploring the bend center (1). In consequence, the center was shown to be present in the sequence ranging from position near 270 to the 3'-terminus and estimated to be located around position 340.