staff

Annick Mutero

Research assistant in Drosophila bithorax complex

  • T: +41 22 379 6756
  • office 3004a (Sciences III)
  • The BEN Domain Protein Insensitive Binds to the Fab-7 Chromatin Boundary To Establish Proper Segmental Identity in Drosophila Genetics 2018 Aug;():. genetics.118.301259. 10.1534/genetics.118.301259.

    abstract

    Boundaries (insulators) in the bithorax complex (BX-C) delimit autonomous regulatory domains that orchestrate the parasegment (PS)-specific expression of the BX-C homeotic genes. The boundary separates the and regulatory domains, which control Abd-B expression in PS11 and PS12, respectively. This boundary is composed of multiple functionally redundant elements and has two key functions: it blocks crosstalk between and and facilitates boundary bypass. Here, we show that two BEN domain protein complexes, Insensitive and Elba, bind to multiple sequences located in the nuclease hypersensitive regions. Two of these sequences are recognized by both Insv and Elba and correspond to a CCAATTGG palindrome. Elba also binds to a related CCAATAAG sequence, while Insv does not. However, the third Insv recognition sequences is ~100 bp in length and contains the CCAATAAG sequence at one end. Both Insv and Elba are assembled into large complexes (~420 kD and ~265-290 kD, respectively) in nuclear extracts. Using a sensitized genetic background we show that the Insv protein is required for boundary function, and that PS11 identity is not properly established in mutants. This is the first demonstration that a BEN domain protein is important for the functioning of an endogenous fly boundary.

    view more details on Pubmed

  • Initiator elements function to determine the activity state of BX-C enhancers. PLoS Genet. 2010 ;6(12):e1001260. 10.1371/journal.pgen.1001260. PMC3009686.

    abstract

    A >300 kb cis-regulatory region is required for the proper expression of the three bithorax complex (BX-C) homeotic genes. Based on genetic and transgenic analysis, a model has been proposed in which the numerous BX-C cis-regulatory elements are spatially restricted through the activation or repression of parasegment-specific chromatin domains. Particular early embryonic enhancers, called initiators, have been proposed to control this complex process. Here, in order to better understand the process of domain activation, we have undertaken a systematic in situ dissection of the iab-6 cis-regulatory domain using a new method, called InSIRT. Using this method, we create and genetically characterize mutations affecting iab-6 function, including mutations specifically modifying the iab-6 initiator. Through our mutagenesis of the iab-6 initiator, we provide strong evidence that initiators function not to directly control homeotic gene expression but rather as domain control centers to determine the activity state of the enhancers and silencers within a cis-regulatory domain.

    view more details on Pubmed

Nothing to show yet