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

Abstract

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.

Nuclear halo from Bradysia hygida (Diptera:Sciaridae) salivary gland polytene cells

“…After that, it was imperative not to relax the loops too much with extensive time in LIS buffer incubation. For D. melanogaster preparations LIS incubation was carried out for 5 minutes (Mikami et al, 2001) but the same procedure took 15 minutes in B. hygida polytene nuclei fractions. The salivary gland tissue complexity (Laicine et al, 1984)…”

“…These regions have been related to specific sequences located in Drosophila polytene chromosome bands and interbands, but the investigations are carried out using nuclei other than the polytene nuclei fraction (Iarovaia et al, 1996;Mirkovittch et al, 1986;Schwartz et al,1999). In a previous paper, our laboratory reported that in hypo-osmotic buffers and during the absence of polyamines such as spermine and spermidine, it is possible to obtain halos from Drosophila salivary gland polytene nuclei using LIS detergent (lithium diiodosalicylate) for protein extraction (Mikami et al, 2001). Regarding the beginning of the characterization of the nuclear matrix of the Bradysia hygida salivary gland polytene nucleus, this trial describes the protocol for recovering nuclear halos of Sciaridae, since this salivary gland and polytene nucleus are very different from the ones observed in Drosophila.…”