mRNA is first detected at low levels in early pupae, peaks at 24% APF and then returns to basal levels by 43% APF.
transcripts are found predominantly within the interommatidial cell at 24 hours APF.
transcript is expressed from embryonic stage 4-14. Embryonic stage 4 expression is initially in a pattern of seven stripes, which soon fades. Subsequently, rst
is expressed in dorsally in the procephalic region and in the amnioserosa anlage. At stage 8, rst
is expressed in mesectodermal cells in a segmental pattern. At stage 9, rst
is expressed at the dorsal midline and in mesodermal cells. Dorsal midline expression intensifies during stage 10-11, as expression begins in visceral muscle progenitors. At stage 12, rst
has strong expression in most mesodermal cells as dorsal midline expression fades. At stages 13-14, expression is in muscle founder cells, and in fusion-competent myoblasts.
transcripts are expressed throughout development with peaks in embryonic and pupal stages. In late stage 11 embryos, transcripts are detected in lateral mesodermal cell clusters, in the midline, in cell clusters in the mandibular, maxillary, and labial buds, and in the clypeolabrum. In late third instar larvae, strong signal is observed in the imaginal discs and in the outer optic anlagen. In the eye disc, expression starts just in front of the morphogenetic furrow. In pupae, expression is observed in the lamina and in subpopulations of medullar cells. At 36hr, retinal expression is restricted to cells between the ommatidiial clusters (ie. to presumptive secondary and tertiary pigment cells and to cells of the bristle complex). Expression is then down-regulated in the retina and transcripts can no longer be detected 72hr after puparium formation.