The 3.2 kb Myb transcript is detected throughout development. Myb transcript is detected mainly in proliferating tissues, though expression is seen at lower levels in some post-mitotic tissues. Expression is uniform and high in preblastoderm embryos, and continues to be high during cellular blastoderm formation and germ band extension. Message is less uniform in contracted germ band embryos, with no expression seen in the amnioserosa, and low expression in the salivary glands. Later in embryogenesis, Myb transcript is high only in the CNS. In climbing third instar larvae, tissues contributing to the adult express Myb at high levels: imaginal disc, brain, ventral ganglion, testes, ovaries, and nests of imaginal cells in the gut. Expression in these tissues continues in the early pupa, with additional expression detected in histoblasts and epithelial cells of the developing imaginal gut. Myb levels decline in everted imaginal tissues. Ovary, testis, and neural tissue continue to express Myb transcript through pupal development. Myb is detected at low levels in the brain and thoracic ganglia of adults, and expression is high in adult testes and ovaries.

(Katzen and Bishop, 1996)