Abstracts (poster) - Wissenschaft Online

Martin Herold, Dorte Bohla, Marek Bartkuhn, Imke Panzer, Rainer Renkawitz
CTCF, the highly conserved boundary factor of Drosophila and
vertebrates
Insulator sequences guide the function of distantly located enhancer elements to the
appropriate target genes by blocking inappropriate interactions. In Drosophila dCTCF is
the only insulator binding protein known to be conserved in vertebrates. We found that
the structurally related factors dCTCF and Su(Hw) have distinct binding targets, whereas
the Su(Hw) interacting factor CP190 largely overlaps with dCTCF binding sites. Analysis
of the bithorax complex revealed that six of the borders between the parasegment
specific regulatory domains are bound by dCTCF and CP190 in vivo and some of them
act as insulators (1,2). We have shown that the function of one boundary, Fab-8, is
dependent on binding of dCTCF, as mutations of the dCTCF target sites abolish Fab-8
insulator function (1,3).
Since dCTCF is critical for Fab-8 enhancer blocking in Drosophila S2 cells, we used cells
with integrated reporter constructs. These contain variants of the Fab-8 insulator
(Ciavatta et al., 2007), which allow us to investigate the interaction between dCTCF and
CP190 by RNAi experiments and studies of other dCTCF interaction partners, which we
identified by Flag-tag IPs.
As it is known, that CTCF mediates the interchromosomal colocalization between
Igf2/H19 and Wsb1/Nf1 (Ling et al., 2007) we wanted to investigate the influence of
dCTCF on the 3D conformation of the chromatin. For this purpose we use 3C-assay to
analyse the interaction between dCTCF target sites in the presence and absence of
dCTCF.
Literature
1. Mohan, M., Bartkuhn, M., Herold, M., Philippen, A., Heinl, N., Bardenhagen, I., Leers,
J., White, R. A., Renkawitz-Pohl, R., Saumweber, H., and Renkawitz, R. (2007) Embo J
26(19)
2. Holohan, E. E., Kwong, C., Adryan, B., Bartkuhn, M., Herold, M., Renkawitz, R.,
Russell, S., and White, R. (2007) PloS Genet 3(7)
3. Moon, H. et al, (2005) EMBO Rep 6(2)
contact:
Dipl. Biol. Martin Herold
Justus-Liebig-Universität Giessen
Institut für Genetik
martin.herold@bio.uni-giessen.de
Heinrich-Buff-Ring 58
35392 Giessen (Germany)