Mireia Angulo

Publications (2)13.23 Total impact

• Source

  Available from: PubMed Central

  Article: Functional dissection of the ash2 and ash1 transcriptomes provides insights into the transcriptional basis of wing phenotypes and reveals conserved protein interactions.

  Sergi Beltran, Mireia Angulo, Miguel Pignatelli, Florenci Serras, Montserrat Corominas
  [show abstract] [hide abstract]
  ABSTRACT: The trithorax group (trxG) genes absent, small or homeotic discs 1 (ash1) and 2 (ash2) were isolated in a screen for mutants with abnormal imaginal discs. Mutations in either gene cause homeotic transformations but Hox genes are not their only targets. Although analysis of double mutants revealed that ash2 and ash1 mutations enhance each other's phenotypes, suggesting they are functionally related, it was shown that these proteins are subunits of distinct complexes. The analysis of wing imaginal disc transcriptomes from ash2 and ash1 mutants showed that they are highly similar. Functional annotation of regulated genes using Gene Ontology allowed identification of severely affected groups of genes that could be correlated to the wing phenotypes observed. Comparison of the differentially expressed genes with those from other genome-wide analyses revealed similarities between ASH2 and Sin3A, suggesting a putative functional relationship. Coimmunoprecipitation studies and immunolocalization on polytene chromosomes demonstrated that ASH2 and Sin3A interact with HCF (host-cell factor). The results of nucleosome western blots and clonal analysis indicated that ASH2 is necessary for trimethylation of the Lys4 on histone 3 (H3K4). The similarity between the transcriptomes of ash2 and ash1 mutants supports a model in which the two genes act together to maintain stable states of transcription. Like in humans, both ASH2 and Sin3A bind HCF. Finally, the reduction of H3K4 trimethylation in ash2 mutants is the first evidence in Drosophila regarding the molecular function of this trxG gene.
  Genome biology 02/2007; 8(4):R67. · 6.63 Impact Factor
• Article: Activation and repression activities of ash2 in Drosophila wing imaginal discs.

  Mireia Angulo, Montserrat Corominas, Florenci Serras
  [show abstract] [hide abstract]
  ABSTRACT: Polycomb (PcG) and trithorax (trxG) group genes are chromatin regulators involved in the maintenance of developmental decisions. Although their function as transcriptional regulators of homeotic genes has been well documented, little is known about their effect on other target genes or their role in other developmental processes. In this study, we have used the patterning of veins and interveins in the wing as a model with which to understand the function of the trxG gene ash2 (absent, small or homeotic discs 2). We show that ash2 is required to sustain the activation of the intervein-promoting genes net and blistered (bs) and to repress rhomboid (rho), a component of the EGF receptor (Egfr) pathway. Moreover, loss-of-function phenotypes of the Egfr pathway are suppressed by ash2 mutants, while gain-of-function phenotypes are enhanced. Our results also show that ash2 acts as a repressor of the vein L2-organising gene knirps (kni), whose expression is upregulated throughout the whole wing imaginal disc in ash2 mutants and mitotic clones. Furthermore, ash2-mediated inhibition of kni is independent of spalt-major and spalt-related. Together, these experiments indicate that ash2 plays a role in two processes during wing development: (1) maintaining intervein cell fate, either by activation of intervein genes or inhibition of vein differentiation genes; and (2) keeping kni in an off state in tissues beyond the L2 vein. We propose that the Ash2 complex provides a molecular framework for a mechanism required to maintain cellular identities in the wing development.
  Development 11/2004; 131(20):4943-53. · 6.60 Impact Factor