Acetylation of chromosome squashes of Drosophila melanogaster decreases the background in autoradiographs from hybridization with [125I]-labeled RNA.

Abstract

DNA in prepared chromosomes from the larval salivary glands of Drosophila melanogaster was hybridized with [125I]-labeled 5S and tRNA from the same organism. Autoradiography revealed that radioactivity was frequently bound to all regions of the slides, masking labeling of the chromosomes. Acetylation of the preparations before hybridization prevented the formation of this background and revealed the specific chromosomal sites.

The selection, expression, and organization of a set of head-specific genes in Drosophila

“…Procedures for salivary gland preparation and in situ hybridization were the same as described (Hayashi et al, 1978;Strobe1 et al, 1979). Hybridization was done under 22-mm2 coverslips at 37°C for 16 hr in 15 ~1 buffer containing 50% deionized formamide, 0.4 M NaCl, 0.01 M Pipes, pH 6.4, and a heat-denatured nick-translated DNA probe (-3 X lo5 cpm/slide).…”

Detection of Aleutian Disease Virus DNA in Tissues of Naturally Infected Mink

“…Post-fixation of the cells was done by treatment in freshly prepared 5~ paraformaldehyde for 2 h in the dark (Haase et al, 1984). The slides were washed twice for 5 min each in 2 × SSC, then rinsed in distilled water and acetylated (Hayashi et al, 1978). After dehydration in a graded ethanol series, DNA was denatured by placing the slides in a solution containing 95% de-ionized formamide in 0.1 × SSC at 65 °C for 10 min.…”

cAMP regulates P450scc gene expression by a cycloheximide-insensitive mechanism in cultured mouse Leydig MA-10 cells.

“…§1734 solely to indicate this fact. (27) and then prehybridized in buffer (26) containing heparin (140 pug/ml), Escherichia coli DNA (50 ,ug/ml), and poly(A) (25 ,ug/ml). Slides were covered with a coverslip, hybridized in the same buffer containing 3H-labeled human P450scc RNA (100 pg/,ul) at 37°C overnight.…”