Bar homeodomain proteins are anti-proneural in the Drosophila eye: transcriptional repression of atonal by Bar prevents ectopic retinal neurogenesis.
نویسندگان
چکیده
Atonal (Ato)/Math (Mammalian atonal homolog) family proneural proteins are key regulators of neurogenesis in both vertebrates and invertebrates. In the Drosophila eye, Ato is essential for the generation of photoreceptor neurons. Ato expression is initiated at the anterior ridge of the morphogenetic furrow but is repressed in the retinal precursor cells behind the furrow to prevent ectopic neurogenesis. We show that Ato repression is mediated by the conserved homeobox proteins BarH1 and BarH2. Loss of Bar causes cell-autonomous ectopic Ato expression, resulting in excess photoreceptor clusters. The initial ommatidial spacing at the furrow occurs normally in the absence of Bar, suggesting that the ectopic neurogenesis within Bar mutant clones is not due to the lack of Notch (N)-dependent lateral inhibition. Targeted misexpression of Bar is sufficient to repress ato expression. Furthermore, we provide evidence that Bar represses ato expression at the level of transcription without affecting the expression of an ato activator, Cubitus interruptus (Ci). Thus, we propose that Bar is essential for transcriptional repression of ato and the prevention of ectopic neurogenesis behind the furrow.
منابع مشابه
Induction and autoregulation of the anti-proneural gene Bar during retinal neurogenesis in Drosophila.
Neurogenesis in Drosophila eye imaginal disc is controlled by interactions of positive and negative regulatory genes. The basic helix-loop-helix (bHLH) transcription factor Atonal (Ato) plays an essential proneural function in the morphogenetic furrow to induce the formation of R8 founder neurons. Bar homeodomain proteins are required for transcriptional repression of ato in the basal undiffere...
متن کاملDrosophila TRAP230/240 are essential coactivators for Atonal in retinal neurogenesis.
The TRAP (thyroid hormone receptor associated proteins)/Mediator complex serves as a transcriptional coactivator. In Drosophila, Kohtalo (Kto) and Skuld (Skd), homologs of TRAP subunits, TRAP230 and TRAP240, respectively, are necessary for eye development. However, the transcriptional activators that require Kto and Skd have not been identified. Here we provide evidence that Kto and Skd are ess...
متن کاملNovel function of the class I bHLH protein Daughterless in the negative regulation of proneural gene expression in the Drosophila eye.
Two types of basic helix-loop-helix (bHLH) family transcription factor have functions in neurogenesis. Class II bHLH proteins are expressed in tissue-specific patterns, whereas class I proteins are broadly expressed as general cofactors for class II proteins. Here, we show that the Drosophila class I factor Daughterless (Da) is upregulated by Hedgehog (Hh) and Decapentaplegic (Dpp) signalling d...
متن کاملProneural enhancement by Notch overcomes Suppressor-of-Hairless repressor function in the developing Drosophila eye
BACKGROUND The receptor protein Notch plays a conserved role in restricting neural-fate specification during lateral inhibition. Lateral inhibition requires the Notch intracellular domain to coactivate Su(H)-mediated transcription of the Enhancer-of-split Complex. During Drosophila eye development, Notch plays an additional role in promoting neural fate independently of Su(H) and E(spl)-C, and ...
متن کاملAtonal, rough and the resolution of proneural clusters in the developing Drosophila retina.
In the developing Drosophila retina, the proneural gene for photoreceptor neurons is atonal, a basic helix-loop-helix transcription factor. Using atonal as a marker for proneural maturation, we examine the stepwise resolution of proneural clusters during the initiation of ommatidial differentiation in the developing eye disc. In addition, evidence is provided that atonal is negatively regulated...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Development
دوره 130 24 شماره
صفحات -
تاریخ انتشار 2003