Fig 3. Cytological mapping of the binding sites of anti-PCNA antibodies breaks down the S phase of the endocycle into six substages and assigns rb-bands to replication completion groups.
First column: The replication pattern of bands in the regions 43F-46B of polytene chromosome 2R as visualized by antibodies against PCNA (red) on SuURES (A) and Oregon R (B–F) polytene chromosomes. Top to bottom: consecutive substages of the S phase, from the earliest (A) to latest (F). (A) “Black” bands not labeled yet. (B–F) Discontinuous labeling. Band designation appears at the substages at which these bands end replication. Second column: superimposed images, immunolocalization and phase contrast. Third column: Replication pattern-based substages of S phase, where ER is the earliest substage and LR1–LR5 are the subsequent provisionally late substages. Fourth column: Each rb-band was assigned to one of five groups, LR1 through LR5, according to the substage at which this rb-band ends replication. A small group of bands with no PCNA at LR1 was classified as LR0. For each substage, all replicating groups and all bands that completed replication are indicated (red text).