Magor K A, Wright J M
Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada.
Mol Biol Rep. 1992 May;16(2):105-15. doi: 10.1007/BF00419756.
We have identified two novel chromosomal proteins from Physarum polycephalum using a protein blotting DNA-binding assay. A fraction of these proteins was readily released from nuclei by solutions of moderate ionic strength (0.15 N-0.35 M NaCl) or mild nuclease treatment and appear associated with chromatin that is nucleosome-free. A significant proportion of these proteins, however, was not released from nuclei by solutions of high ionic strength (1.6 M NaCl) or treatment with excess nuclease. These results suggest that these chromosomal proteins are distributed between transcriptionally-competent and inert domains of chromatin. Both proteins preferentially and tenaciously bound duplex DNA, especially to the alternating B-DNA conformation displayed by the synthetic sequence, poly d(A-T).poly d(A-T).
我们通过蛋白质印迹DNA结合测定法，从多头绒泡菌中鉴定出了两种新型染色体蛋白。这些蛋白中的一部分很容易通过中等离子强度（0.15 N - 0.35 M NaCl）的溶液或温和的核酸酶处理从细胞核中释放出来，并且似乎与无核小体的染色质相关。然而，相当一部分这些蛋白不能通过高离子强度（1.6 M NaCl）的溶液或用过量核酸酶处理从细胞核中释放出来。这些结果表明，这些染色体蛋白分布在染色质的转录活性区域和惰性区域之间。这两种蛋白都优先且牢固地结合双链DNA，特别是与合成序列聚d(A-T).聚d(A-T)所呈现的交替B-DNA构象结合。
