Sa. Demakov et al., CLONING AND MOLECULAR-GENETIC ANALYSIS OF DROSOPHILA-MELANOGASTER INTERBAND DNA, MGG. Molecular & general genetics, 238(3), 1993, pp. 437-443
Interband DNA of Drosophila melanogaster polytene chromosomes was stud
ied using a novel approach based on the electron microscopic (EM) anal
ysis of chromosome regions carrying DNA fragements of known molecular
genetic composition, inserted by P element-mediated transformation. In
sertion of such fragments predominantly into interbands makes it possi
ble to clone interband DNA by constructing genomic libraries from tran
sformed strains and probing them with the insert DNA. The transformed
strain P[Hsp70:Adh](61C) has insertion in the 61C7-8 interband on the
left arm of chromosome 3. This DNA consists of part of the hsp70 gene
promoter fused to the coding region of the Adh gene, and is flanked on
either side by P element sequences. We constructed a genomic library
from DNA of this strain and isolated a clone containing the insert and
the interband DNA. Subsequently the genomic library of wild-type stra
in was probed with a subclone composed of interband DNA only. We have
thus isolated a clone containing the entire native interband. 1289 bp
of interband DNA was sequenced and found to be AT-rich (53.4%) with nu
merous regions of overlapping direct and inverted repeats, regulatory
sites, and two overlapping open reading frames (ORFs).