title: Hrp48 attenuates Sxl expression to allow for proper notch expression and signaling in wing development.
abstract: Different signaling pathways are deployed in specific developmental contexts to generate sexually dimorphic traits. Recently, Sex-lethal (Sxl), the female determinant in Drosophila melanogaster, was shown to down-regulate Notch (N) signaling to accomplish sex-specific patterning. Paradoxically, however, both Sxl and N are ubiquitously expressed in all of the female cells. This raises a key question as to how, during monomorphic female development, N signaling escapes the negative impact of Sxl. Here, we uncover a regulatory loop involving Hrp48, an abundant Drosophila hnRNP, Sxl and N. Phenotypic consequences of the partial loss of hrp48 resemble that of N but are more pronounced in females than in males. Likewise, N levels are drastically diminished only in females. Interestingly, monomorphic female tissues including wing, eye and antennal discs display considerable increase in Sxl amounts. Finally, female-specific attenuation of N signaling is rescued upon simultaneous removal of Sxl. Thus, our data demonstrate that in monomorphic contexts, Hrp48 functions as a moderator of Sxl expression to achieve adequate levels of N receptor production and signaling. We propose that it is critical to modulate the activities of the master determinant underling sexual dimorphism, to ensure that it does not function inappropriately in monomorphic tissues and disrupt their development.
authors.affiliation: Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel.
authors.forename: Yaron
authors.initials: Y
authors.lastname: Suissa
authors.forename: Yossi
authors.initials: Y
authors.lastname: Kalifa
authors.forename: Tama
authors.initials: T
authors.lastname: Dinur
authors.forename: Patricia
authors.initials: P
authors.lastname: Graham
authors.forename: Girish
authors.initials: G
authors.lastname: Deshpande
authors.forename: Paul
authors.initials: P
authors.lastname: Schedl
authors.forename: Offer
authors.initials: O
authors.lastname: Gerlitz
mesh_terms: D000483:Alleles; D000818:Animals; D003433:Crosses, Genetic; D029721:Drosophila Proteins / Q000378:metabolism* / Q000502:physiology*; D004331:Drosophila melanogaster / Q000378:metabolism*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D034441:Heterogeneous-Nuclear Ribonucleoproteins / Q000378:metabolism / Q000502:physiology*; D008297:Male; D008938:Mitosis; D008954:Models, Biological; D016601:RNA-Binding Proteins / Q000378:metabolism*; D051880:Receptors, Notch / Q000378:metabolism*; D012737:Sex Factors; D015398:Signal Transduction; D014921:Wings, Animal / Q000196:embryology
chemical_list: D029721:Drosophila Proteins; D034441:Heterogeneous-Nuclear Ribonucleoproteins; C487427:Hrb27C protein, Drosophila; D016601:RNA-Binding Proteins; D051880:Receptors, Notch; C067777:Sxl protein, Drosophila