Question

In mammalian cells, genes that are expressed in a particular cell are reported to undergo replication during the first half of S phase, and genes not expressed in that cell are replicated in the latter half of S phase.

Briefly describe an experiment that could lead to this conclusion. You might consider approaches that involve 5-bromouracil incorporation.

Rank from the first step to the last step. To rank items as equivalent, overlap them.

Selectively isolation early-replicatingLabeling with 5-bromodeoxyuridine genes by equilibrium gradient centrifugation after an early BUdR early labeling interval, and isolate late- replicating regions of the genome. Adding thymidine to a cell culture allows all cells to proceed through the cycle until they reach early S phase, whereupon they stop progressing. in S-phase would increase the density of genomic regions undergoing replication early Identification and quantitation gene sequences that have undergone replication, by reannealing with cloned DNA probes and identifying genes that have undergone a doubling Transferring the cells to thymidine- free medium allows them all to initiate S phase simultaneously.

Answer 1

Selectively isolation early-replicating genes by equilibrium gradient Transferring the cells to thymidine-early in S-phase would increase thecentrifugation after an early BUdk labeling interval, and isolate late- replicating regions of the genome. Adding thymidine to a cell culture allows all cells to proceed through the cycle until they reach early S phase, whereupon they stop progressing Labeling with 5-bromodeoxyuridine free medium allows them all to density of genomic regions undergoing replication early initiate S phase simultaneously. Identification and quantitation gene sequences that have undergone replication, by reannealing with cloned DNA probes and identifying genes that have undergone a doubling