Analysis of DNA Interband Regions 3A5/A6, 3C5-6/C7, and 60E8-9/E10 in Polytene Chromosomes of Drosophila melanogaster

Using electron microscopic (EM) data on the formation of a novel band from theP-element material after its insertion in the interband and the procedure of P-target rescue, DNA interband regions 3A5/A6, 3C5-6/C7, and 60E8-9/E10 of Drosophila melanogasterpolytene chromosomes were cloned and sequenced. EM analysis of the 3C region have shown that the formation of the full-size 3C5-6/C7 interband requires a 880-bp DNA sequence removed by deletion Df(1)fa^swb. A comparison of DNA sequences of six bands, two of which were obtained in the present work and four were described earlier, demonstrated the uniqueness of each of them in the Drosophilagenome and heterogeneity of their molecular organization. Interband 60E8-9/E10 contains gene rpl19transcribed throughout the development, in particular in salivary glands. In the other interbands examined 5" and 3" nontranslated gene regions are located. These results suggest that Drosophilainterbands may contain both housekeeping genes and regulatory sequences of currently inactive genes from adjacent bands.