Visualization of Polytene Chromatin in Mosquito Cell Nuclei Using Three-Dimensional Fluorescence In Situ Hybridization.

Chromosomes are intricately folded within the cell nucleus and interact with peripheral nuclear proteins. The chromatin architecture has a profound effect on how the genome is organized. 3D-FISH is a powerful technique that can reveal the structural and functional organization of chromosomes in the nuclear space. Here, we present a protocol for visualizing specific genomic regions in whole-mount paraformaldehyde-fixed cell nuclei of Anopheles mosquitoes. This protocol was tested in our laboratories and has been showed to be effective and reliable for visualizing genomic regions of various lengths-from 1-kb gene-scale fragments to chromosome-scale segments of DNA.