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TY - JOUR AU - Hentschel, Christopher C. PY - 1982 DA - 1982/02/01 TI - Homocopolymer sequences in the spacer of a sea urchin histone gene repeat are sensitive to S1 nuclease JO - Nature SP - 714 EP - 716 VL - 295 IS - 5851 AB - The concept of specific functional elements in genes comprising localized or transient structural discontinuities, such as Z-DNA or cruciforme, is becoming increasingly plausible1–6. Cruciforms were first detected as supercoil-dependent single-strand nuclease (S1)-sensitive sites characterized by hyphenated inverted repeat DNA sequences2,3. Here I describe examples of a novel type of S1 nuclease site found in a sea urchin histone gene repeat and characterized by homocopolymer sequences. Endonucleolytic cleavage within these sequences does not depend on supercoiling, is highly sensitive to the salt concentration and shows a reproducible pattern of maxima and minima. This type of S1 sensitivity may reflect the potential for out-of-register DNA slippage in such sequences and I speculate that related slippage events in vivo could lead to their acting as foci for recombinational events. SN - 1476-4687 UR - https://doi.org/10.1038/295714a0 DO - 10.1038/295714a0 ID - Hentschel1982 ER -