pannier encodes two structurally related isoforms that are differentially expressed during Drosophila development and display distinct functions during thorax patterning

Abstract

Previous studies have shown that the pannier (pnr) gene of Drosophila encodes a GATA transcription factor which is involved in various biological processes, including heart development, dorsal closure during embryogenesis as well as neurogenesis and regulation of wingless (wg) expression during imaginal development. We demonstrate here that pnr encodes two highly related isoforms that share functional domains but are differentially expressed during development. Moreover, we describe two genomic regions of the pnr locus that drive expression of a reporter in transgenic flies in patterns that recapitulate essential features of the expression of the isoforms, suggesting that these regions encompass crucial regulatory elements. These elements contain, in particular, sequences mediating regulation of expression by Decapentaplegic (Dpp) signaling, during both embryogenesis and imaginal development. Analysis of pnr alleles reveals that the isoforms differentially regulate expression of both wg and proneural achaete/scute (as/sc) targets during imaginal development. Pnr function has been demonstrated to be necessary both for activation of wg and, together with U-shaped (Ush), for its repression in the dorsal-most region of the presumptive notum. Expression of the isoforms define distinct longitudinal domains and, in this regard, we importantly show that the dual function of pnr during regulation of wg is achieved by one isoform repressing expression of the morphogen in the dorsal-most region of the disc while the other laterally promotes activation of the notal wg expression. Our study provides novel insights into pnr function during Drosophila development and extends our knowledge of the roles of prepattern factors during thorax patterning.

The kinase Sgg modulates temporal development of macrochaetes inDrosophilaby phosphorylation of Scute and Pannier

“…See supplementary material Table S1 for primer sequences. Note that Pnr exists in two isoforms (Fromental-Ramain et al, 2008), with conserved Sgg phosphorylation sites: in this work, the pnrb isoform was used.…”

“…Interestingly it has been shown that the Drosophila transcription factor Mad is also a target of Sgg and that phosphorylation-resistant Mad proteins are hyperactive (Eivers et al, 2009). Mad is activated by Dpp/TGFb signalling, which in turn regulates expression of both pnr and the Iro-C genes in the thorax (Sato and Saigo, 2000;Tomoyasu et al, 2000;Shi and Massague, 2003;Letizia et al, 2007;Fromental-Ramain et al, 2008) (Fig. 5).…”

Analysis of the Neurogenesis: Prepattern gene network сontrolling the first stage in Drosophila melanogaster bristle pattern development

“…Генная сеть Neurogenesis:Prepattern руют транскрипцию u-shaped (Hannon et al, 1991;Tsai et al, 1991;Ramain et al, 1993;Cubadda et al, 1997;Haenlin et al, 1997;Fromental-Ramain et al, 2008. На третьем уровне управления сосредоточены эле-мен ты контроля за функционированием основного клю-чевого объекта сети с максимальной связностью -про-нейральных генов комплекса achaete-scute.…”

“…Наработка Wg приводит к активации sgg, а киназа Sgg фосфорилирует Pnrβ, преобразуя его в неак-тивную форму. Таким образом, превышение содержания Pnrα над содержанием Pnrβ в клетках имагинального диска закрывает для них нейральный путь дифференцировки, полностью исключая возможность активации генов AS-C. Этот контур функционирует в пределах презумптивного нотума и обеспечивает уточнение взаимного распо-ложения пронейральных кластеров (Sato, Saigo, 2000;Fromental-Ramain et al, 2008Yang et al, 2012).…”

Drosophila Model of Congenital Heart Diseases

“…The Drosophila model allowed the extensive genetic screening and functional analysis of Tinman (NKX2. 5 Yin et al, 1997;Akasaka et al, 2006;Zaffran et al, 2006;Qian et al, 2011;Ryu et al, 2011), Hand (dHAND, eHAND, Han andOlson, 2005; www.intechopen.com Lo et al, 2007), tailup/isl-1 (Islet, Tao et al, 2007;Mann et al, 2009), Pannier (GATA4, Alvarez et al, 2003Fromental-Ramain et al, 2008;Qian et al, 2008;Qian and Bodmer, 2009), Neuromancer-1/-2 (TBX20, Miskolczi-McCallum et al, 2005;Qian et al, 2005a;Leal et al, 2009), and Dorsocross-1/-2/-3 (TBX5, and revealed a conserved cardiac transcription factor network responsible for heart specification (Olson, 2006). Drosophila and vertebrates also share the same inductive and instructive signaling pathways (Wnt, FGF, BMPs, for review see Frasch, 1999;Cripps and Olson, 2002) during early heart development.…”