unpg transcripts are first detected in 4-8hr embryos and are expressed throughout embryogenesis. Levels decrease during larval stages and then increase during pupal and adult stages. unpg tanscripts are first detected by in situ at stage 8 in a subset of neuroblasts of the midline. These cells divide to generate neuroblasts and neurons of the CNS that largely correspond to the en-expressing cells. By stage 14, CNS expression is restricted to a few cells per segment. Outside of the CNS, expression is first observed in two clusters of ectodermal cells located laterally with the labial and first thoracic segments at stage 9. By stage 11, expression is seen in 15-20 cells around the anterior part of the first tracheal pit. By stage 13, expression is detected in a few cells close to the dorsal midline. These cells appear to form long cytoplasmic branches that prefigure the cerebral branches of the tracheal system. As the germband retracts, a new expression domain is seen within the invaginated tracheal pits in segments T1-A7. During germband retraction, these precursor cells extend ventrally and dorsally. By stage 14, the ganglionic branch in each hemisegment consists of 7-9 unpg-expressing cells whose cell bodies appear to form a continuous chain that penetrates the CNS of stage 14 embryos. Double labeling experiments show that unpg expression outside of the CNS is limited to cells of the cerebral and ganglionic branches of the tracheal system during embryonic development.

(Chiang et al., 1995)

The protein and transcript expression patterns of unpg are indistinguishable. unpg protein is first detected at stage 8 in a subset of neuroblasts of the midline. These cells divide to generate neuroblasts and neurons of the CNS that largely correspond to the en-expressing cells. By stage 14, CNS expression is restricted to a few cells per segment. Outside of the CNS, expression is first observed in two clusters of ectodermal cells located laterally with the labial and first thoracic segments at stage 9. By stage 11, expression is seen in 15-20 cells around the anterior part of the first tracheal pit. By stage 13, expression is detected in a few cells close to the dorsal midline. These cells appear to form long cytoplasmic branches that prefigure the cerebral branches of the tracheal system. As the germband retracts, a new expression domain is seen within the invaginated tracheal pits in segments T1-A7. During germband retraction, these precursor cells extend ventrally and dorsally. By stage 14, the ganglionic branch in each hemisegment consists of 7-9 unpg-expressing cells whose cell bodies appear to form a continuous chain that penetrates the CNS of stage 14 embryos. Double labeling experiments show that unpg expression outside of the CNS is limited to cells of the cerebral and ganglionic branches of the tracheal system during embryonic development.

(Chiang et al., 1995)