Restricted to the developing gut and central nervous system (CNS). Detected from at stage 7, where it is expressed in the early germ band. By stage 11, when the germ band is fully extended, it is expressed strongly in the ventral neuroectoderm, which represents the progenitor of the CNS. At this time, a small region of particularly strong expression is visible at the tip of the extended germ band marking the proctodeum (the primordial hindgut) and expression is also visible in the anterior midgut and the foregut primordial region known as the stomodeum. Expression then persists in both the emerging gut and nervous system during the next three developmental stages (12-14). Strong expression in the primordial midgut is rapidly down-regulated prior to stage 15, by when the presumptive midgut has closed both ventrally and dorsally and is largely established. However, expression persists in the hindgut as it continues to develop by projecting towards the antero-dorsal region of the embryo and is also evident in differentiating components of the foregut, which might include the stomatogastric nervous system. Interestingly, it is expressed strongly throughout the developing CNS and the intensity of this staining is maintained through stage 16 during major periods of developmental reorganization, while expression in regions of the gut is rapidly down-regulated. Expression continues in the CNS late into stage 17, but is also clearly reduced by the end of stage 17 immediately prior to hatching. Expressed during all subsequent developmental stages from first instar larvae through to adulthood. Partially edited. Target of Adar.