抄録
During in vitro incubation of thymus cells, proteins which have affinity for single stranded DNA (ss-DNA) are released into the medium. When the thymus cells were labeled with [3H]leucine for 5 h, about 3.5 % of the labeled leucine that was taken up by the cells was released into the medium in trichloroacetic acid-insoluble form, and about 2 % of the total radioactivity in the released proteins bound to the ss-DNA-cellulose. When the [3H]leucine labeled ss-DNA-binding proteins were incubated with spleen cells for 30 min at 37°C, about 2.6 % of the added [3H]labeled ss-DNA-binding proteins re-mained in the cells. In experiments using electron microscope autoradiography, some of the ss-DNA-binding proteins were found to enter the nuclei of spleen cells. Nuclei were isolated from these treated cells and radioactive proteins were recovered. Analysis of these proteins with sodium dodecyl sulfate gel electrophoresis gave five or six components whose molecular weights ranged from 1.4 to 7.2 × 104.
