Replication Origins in Xenopus Egg Extract Are 5-15 Kilobases Apart and Are Activated in Clusters That Fire at Different Times Export

@article{citeulike:1182049, abstract = {When Xenopus eggs and egg extracts replicate DNA, replication origins are positioned randomly with respect to DNA sequence. However, a completely random distribution of origins would generate some unacceptably large interorigin distances. We have investigated the distribution of replication origins in Xenopus sperm nuclei replicating in Xenopus egg extract. Replicating DNA was labeled with [3H]thymidine or bromodeoxyuridine and the geometry of labeled sites on spread DNA was examined. Most origins were spaced 5-15 kb apart. This regular distribution provides an explanation for how complete chromosome replication can be ensured although origins are positioned randomly with respect to DNA sequence. Origins were grouped into small clusters (typically containing 5-10 replicons) that fired at approximately the same time, with different clusters being activated at different times in S phase. This suggests that a temporal program of origin firing similar to that seen in somatic cells also exists in the Xenopus embryo. When the quantity of origin recognition complexes (ORCs) on the chromatin was restricted, the average interorigin distance increased, and the number of origins in each cluster decreased. This suggests that the binding of ORCs to chromatin determines the regular spacing of origins in this system. 10.1083/jcb.152.1.15}, author = {Blow, Julian J. and Gillespie, Peter J. and Francis, Dennis and Jackson, Dean A.}, citeulike-article-id = {1182049}, citeulike-linkout-0 = {http://dx.doi.org/10.1083/jcb.152.1.15}, citeulike-linkout-1 = {http://www.jcb.org/cgi/content/abstract/152/1/15}, citeulike-linkout-2 = {http://view.ncbi.nlm.nih.gov/pubmed/11149917}, citeulike-linkout-3 = {http://www.hubmed.org/display.cgi?uids=11149917}, day = {2}, doi = {10.1083/jcb.152.1.15}, journal = {J. Cell Biol.}, keywords = {origins\_of\_replication, spermatozoa, xenopus\_laevis}, month = {January}, number = {1}, pages = {15--26}, posted-at = {2007-03-23 18:16:27}, priority = {2}, title = {Replication Origins in Xenopus Egg Extract Are 5-15 Kilobases Apart and Are Activated in Clusters That Fire at Different Times}, url = {http://dx.doi.org/10.1083/jcb.152.1.15}, volume = {152}, year = {2001} }

TY - JOUR ID - citeulike:1182049 L3 - citeulike-article-id:1182049 N2 - When Xenopus eggs and egg extracts replicate DNA, replication origins are positioned randomly with respect to DNA sequence. However, a completely random distribution of origins would generate some unacceptably large interorigin distances. We have investigated the distribution of replication origins in Xenopus sperm nuclei replicating in Xenopus egg extract. Replicating DNA was labeled with [3H]thymidine or bromodeoxyuridine and the geometry of labeled sites on spread DNA was examined. Most origins were spaced 5-15 kb apart. This regular distribution provides an explanation for how complete chromosome replication can be ensured although origins are positioned randomly with respect to DNA sequence. Origins were grouped into small clusters (typically containing 5-10 replicons) that fired at approximately the same time, with different clusters being activated at different times in S phase. This suggests that a temporal program of origin firing similar to that seen in somatic cells also exists in the Xenopus embryo. When the quantity of origin recognition complexes (ORCs) on the chromatin was restricted, the average interorigin distance increased, and the number of origins in each cluster decreased. This suggests that the binding of ORCs to chromatin determines the regular spacing of origins in this system. 10.1083/jcb.152.1.15 IS - 1 JF - J. Cell Biol. EP - 26 TI - Replication Origins in Xenopus Egg Extract Are 5-15 Kilobases Apart and Are Activated in Clusters That Fire at Different Times VL - 152 SP - 15 KW - origins_of_replication KW - spermatozoa KW - xenopus_laevis AU - Blow, Julian AU - Gillespie, Peter AU - Francis, Dennis AU - Jackson, Dean PY - 2001/01/02/ UR - http://dx.doi.org/10.1083/jcb.152.1.15 ER -