Morioka M, Shimada H. Nuclear AP4A-binding activity of sea urchin embryos changes in relation to the initiation of S phase.
Exp Cell Res 1986;
165:429-40. [PMID:
3720857 DOI:
10.1016/0014-4827(86)90596-3]
[Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The AP4A-binding activity of sea urchin embryos was studied using radioactively labelled diadenosine 5',5"'-P1,P4-tetraphosphate (Ap4A). Among various subcellular components that can bind [3H]AP4A, nuclei alone showed the highly specific Ap4A-binding activity which was not influenced by the presence of AP4A, AP5A and GP4G. The addition of an excess amount of ATP only slightly reduced the binding of [3H]AP4A to the nuclei. It was found that AP4A binds to the residual proteinaceous structure of nuclei which was resistant to the extraction with 2 M NaCl. The nuclear AP4A-binding activity fluctuated cyclically during each cell cycle, with a transient increase at the beginning of S phase followed by an abrupt decrease within 10 min. When the initiation of S phase was blocked, the increase in the AP4A-binding activity was also prevented. It seems that the binding of AP4A to the nuclear structural protein is involved in the initiation of S phase.
Collapse