Duhl D M, Gaczynski M, Olinski R, Briggs R C
Department of Biochemistry, A.B. Hancock, Jr. Memorial Laboratory of Vanderbilt University Cancer Center, Nashville, Tennessee 37232-0146.
J Cell Physiol. 1989 Oct;141(1):148-53. doi: 10.1002/jcp.1041410122.
Based on solubility properties, the human myeloid cell nuclear differentiation antigen exists as at least two distinct populations. Most is easily extracted from isolated nuclei in 0.35 M NaCl, while 20 percent resists such treatment. Compared to undigested nuclei, both the amount of myeloid cell nuclear differentiation antigen (MNDA) released from nuclei after DNase I treatment and the amount resisting further extraction in 0.35 M NaCl increased after DNA was digested with DNase I. Under these conditions, there was a concomitant decrease in the amount of MNDA that was extractable with 0.35 M NaCl. Mixing nuclear protein extracts that contain MNDA with nuclei from cells that do not express this protein demonstrated that the MNDA redistributes from the freely soluble form to the nuclear residual fraction as a consequence of DNase I digestion. These data are consistent with a model in which the amount of MNDA that is tightly bound to salt-washed nuclei is held constant in the presence of an excess of unassociated MNDA in the nucleus, and that the level of MNDA binding to this nuclear fraction increases in proportion to the extent of DNA damage resulting from DNase I digestion.
基于溶解性特性，人类髓系细胞核分化抗原至少以两种不同的形式存在。大多数抗原很容易从分离的细胞核中用0.35M氯化钠提取出来，而20%的抗原则抵抗这种处理。与未消化的细胞核相比，用DNA酶I消化DNA后，从细胞核中释放的髓系细胞核分化抗原（MNDA）的量以及在0.35M氯化钠中抵抗进一步提取的量都增加了。在这些条件下，用0.35M氯化钠可提取的MNDA量随之减少。将含有MNDA的核蛋白提取物与不表达该蛋白的细胞的细胞核混合表明，由于DNA酶I的消化，MNDA从自由可溶形式重新分布到核残余部分。这些数据与一个模型一致，即在细胞核中存在过量未结合的MNDA的情况下，紧密结合在盐洗细胞核上的MNDA量保持恒定，并且MNDA与该核部分的结合水平与DNA酶I消化导致的DNA损伤程度成比例增加。
