Fig. 5.

The switch between Chiffon-A and Chiffon-B expression is not regulated at the mRNA level. (A) Male flies expressing the epitope-tagged Chiffon FL transgene were crossed to untagged females (w¹¹¹⁸), and expression of the paternal chiffon gene was assessed in single embryos using qRT-PCR with primers specific for Chiffon-A (using HA forward primer and chiffon 5′ reverse primer) or Chiffon-B (using a chiffon forward primer in the 3′ region and a FLAG reverse primer). Transcript levels were measured in single embryos and are shown relative to RpL32. Single embryos were ranked using the ratio of expression of nanos (nos; early) versus even skipped (eve; late) to provide a relative indication of early versus later developmental stage. Each dot represents a single relative transcript measurement (e.g. chiffon-A/RpL32) for one individual embryo, so that relative levels of Chiffon-A and Chiffon-B mRNA can be compared directly. (B) Schematic of chiffon gene showing Bruno response elements present in the first 1200 bp (N) that are absent from ΔN region.