Identification of the proteins responsible for SAR DNA binding in nuclear matrix of Cucurbita pepo

The nuclear matrices from White bush (Cucurbita pepovar. patisonina)cell nuclei have been isolated using three methods: I, standard procedure involving extraction of cell nuclei with 2 NaCl and 1% X-100; II, the same with pre-treatment of cell nuclei with 0.5 CuS04 (stabilisation step); and III, method with extraction by lithium diiodosalicylate (LIS), and compared the polypeptide pattern. The isolated matrices specifically bind SAR DNA from human β-interferon gene in the exogenous SAR assay and in the gel mobility shift assay. Using IgG against the 32 endonuclease we have found in the DNA-protein blot assay that this protein is one of the proteins binding SAR DNA. have identified three proteins with molecular mass of 65 , 60 and 32 which are responsible for SAR DNA in the gel mobility shift assay experiments.