The homeodomain transcription factor Orthopedia is involved in development of the Drosophila hindgut

Abstract

AbstractBackgroundTheDrosophilahindgut is commonly used model for studying various aspects of organogenesis like primordium establishment, further specification, patterning, and morphogenesis. During embryonic development ofDrosophila, many transcriptional activators are involved in the formation of the hindgut. The transcription factor Orthopedia (Otp), a member of the 57B homeobox gene cluster, is expressed in the hindgut and nervous system of developingDrosophilaembryos, but due to the lack of mutants no functional analysis has been conducted yet.ResultsWe show that two differentotptranscripts, a hindgut-specific and a nervous system-specific form, are present in theDrosophilaembryo. Using an Otp antibody, a detailed expression analysis during hindgut development was carried out. Otp was not only expressed in the embryonic hindgut, but also in the larval and adult hindgut. To analyse the function ofotp, we generated the mutantotpalleleotpGTby ends-out gene targeting. In addition, we isolated two EMS-inducedotpalleles in a genetic screen for mutants of the 57B region. All threeotpalleles showed embryonic lethality with a severe hindgut phenotype. Anal pads were reduced and the large intestine was completely missing. This phenotype is due to apoptosis in the hindgut primordium and the developing hindgut.ConclusionOur data suggest that Otp is another important factor for hindgut development ofDrosophila. As a downstream factor ofbynOtp is most likely present only in differentiated hindgut cells during all stages of development rather than in stem cells.