tup transcripts are detected in the dorsal ectoderm starting in embryonic stage 10. tup transcripts are also present in Mef2-positive myocardial cells.

tup transcript is first detected in stage 10 embryos in the precursors of the dorsal vessel, pharynx, and amnioserosa. By stage 16 expression has narrowed to the dorsal vessel and the alary and pharyngeal muscles. tup CNS expression is detected in stage 12 embryos in subsets of cells in the ventral nerve cord and brain. Expression is not found in neuroblasts, but in neuronal progeny. By stage 13, there are 20 cells expressing tup per hemisegment, and this pattern is retained through embryonic development. Reporter construct expression (BtauMAPT^{isl.H.T:HsapMYC}) indicates that the tup expressing cells are a subset of motor neurons and interneurons.

In embryos, tup can be detected in the cardiac cells of the heart tip, but not in the most anterior cardioblasts, including the pair of anterior cardioblasts.

In early embryonic stage 11, immediately after MP3 division, tup is absent from the H-cell and H-cell sib. Later in stage 11, tup is present in both the H-cell and H-cell sib. By the end of stage 11, tup is present in the H-cell but absent in H-cell sib. Expression in the H-cell remains on through the end of embryogenesis.

tup protein is detected in a broad domain along the dorsal side of the embryo within the ectodermal layer starting in embryonic stage 10. Expression in the cardiogenic mesoderm begins at mid-stage 11 in ~10 small clusters of cells that are also positive for eve. The tup-expressing cells are part of the pericardial lineage. By late stage 11, tup protein expression expands within the cardiogenic mesoderm (is coexpressed with tin throughout the cardogenic mesoderm) and continues in all myocardial cells during embryogenesis. tup is also expressed in at least two of the tin-positive pericardial cells and all odd-expressing pericardial cells in each hemisegment. In lymph glands, tup is only observed in some of the odd-positive cells. tup is also observed in the amnioserosa.

Approximately 50% of adPNs and 80% of lPNs express tup.

tup expression is confined to the most proximal region of the wing disc, which correspons to part of the prospective notum, as the early late first/early second instar larval stage. During second instar and part of third instar, tup is expressed in the entire medial notum area and extends into the lateral notum. In mid-late third instar, strong expression is maintained in the posterior medial and part of the lateral notum. The most lateral region of the posterior notum is free of tup expression.

The pattern of tup protein expression closely matches that of tup transcript expression. CNS expression is detected in subsets of cells in the brain and ventral nerve cord starting at stage 12; the pattern of about 20 tup expressing cells per hemisegment seen by stage 13 is retained through the rest of embryogenesis.