Drosophila Salivary Gland Polytene Nuclear Halo : a New Approach for Polytene Nuclear Matrix Analysis

This work presents a procedure to perform nuclear halos, nuclear matrix with the associated DNA loops, from Drosophila salivary gland polytene nucleus. The purification with hypo-osmotic buffers in the absence of polyamines, as spermine and spermidine, whose function seems to be related to the chromatin compaction, was considered essential. The non-compacted polytene chromosome in the giant nucleus could be used for protein extraction that allows the liberation of the loops. The profile of the DNA matrix and loop fractions, left after nuclear halo digestion with restriction enzyme, confirms the relationship between these fractions suitable for functional analysis. This procedure could be important to obtain a direct relationship between nuclear matrix association and transcription process in the interphase polytene chromosomes of Drosophila salivary gland nucleus.