Michael Johanson
Major Professor: Dr. Craig Coates
M.S. Candidate
"Insulators and Insulator Proteins in the Mosquito Genome."
CTCF is a DNA binding protein that has been identified in vertebrate, drosophilid and mosquito species. Studies in vertebrates and Drosophila demonstrate that this protein plays a role in insulating genes from enhancers and heterochromatin that would otherwise interfere with their normal expression profiles. Orthologs for the Drosophila insulators CP-190, Su(Hw), and GAGA factor have also been identified in the mosquitoes Aedes aegypti and Anopheles gambiae. Using the Patser bioinformatics program, we have identified sequences throughout the Anopheles genome that are similar to the Drosophila CTCF binding site consensus. These sequences are located in chromosomal regions that have been identified by CTCF immunostaining to polytene chromosomes, as well as at euchromatin/heterochromatin boundaries. Two of these sites have been confirmed with the chromatin irnmunopurification (ChiP) assay and were reported previously. The remainder of these potential sites are currently being confirmed with the ChiP assay. We have also developed Aedes aegypti expression profiles of the three other insulator proteins previously mentioned using RT-PCR analysis. This data shows that the CP-190 expression profile mirrors that of CTCF, suggesting that CP-190 may work in conjunction with CTCF in mosquitoes as has been shown in Drosophila.