| First Author | Ainscough JF | Year | 2007 |
| Journal | J Cell Sci | Volume | 120 |
| Issue | Pt 1 | Pages | 115-24 |
| PubMed ID | 17182902 | Mgi Jnum | J:117459 |
| Mgi Id | MGI:3696531 | Doi | 10.1242/jcs.03327 |
| Citation | Ainscough JF, et al. (2007) C-terminal domains deliver the DNA replication factor Ciz1 to the nuclear matrix. J Cell Sci 120(Pt 1):115-24 |
| abstractText | Cip1-interacting zinc finger protein 1 (Ciz1) stimulates DNA replication in vitro and is required for mammalian cells to enter S phase. Here, we show that a significant proportion of Ciz1 is retained in nuclear foci following extraction with nuclease and high salt. This suggests that Ciz1 is normally immobilized by interaction with non-chromatin nuclear structures, consistent with the nuclear matrix. Furthermore, matrix-associated Ciz1 foci strikingly colocalize with sites of newly synthesized DNA in S phase nuclei, suggesting that Ciz1 is present in DNA replication factories. Analysis of green fluorescent protein-tagged fragments indicates that nuclear immobilization of Ciz1 is mediated by sequences in its C-terminal third, encoded within amino acids 708-830. Immobilization occurs in a cell-cycle-dependent manner, most probably during late G1 or early S phase, to coincide with its reported point of action. Although C-terminal domains are sufficient for immobilization, N-terminal domains are also required to specify focal organization. Combined with previous work, which showed that the DNA replication activity of Ciz1 is encoded by N-terminal sequences, we suggest that Ciz1 is composed of two functionally distinct domains: an N-terminal replication domain and a C-terminal nuclear matrix anchor. This could contribute to the formation or function of DNA replication factories in mammalian cells. |
