The male-specific lethal (MSL) complex of Drosophila is responsible for the presence of a monoacetylated isoform of histone H4 (H4Ac16), found exclusively on the X chromosome of males. This particular covalent modification of histone H4 is correlated with a 2-fold enhancement of the transcription of most X-linked genes in Drosophila males, which is the basis of dosage compensation in this organ...

In the preceding article we compared the general organization of polytene chromosomes in four different Drosophila melanogaster cell types. Here we describe experiments aimed at testing for a potential role of three-dimensional chromosome folding and positioning in modulating gene expression and examining specific chromosome interactions with different nuclear structures. By charting the config...

The histone genes of wild-type Drosophila melanogaster are reiterated 100-150 times per haploid genome and are located in the segment of chromosome 2 that corresponds to polytene bands 39D2-3 to E1-2. The influence of altered histone gene multiplicity on chromatin structure has been assayed by measuring modification of the gene inactivation associated with position effect variegation in genotyp...

Data were collected on the distribution of ten families of transposable elements among fourteen X chromosomes isolated from a natural population of Drosophila melanogaster, by means of in situ hybridization to polytene chromosomes. It was found that, with the exception of roo, the copy number per chromosome followed a Poisson distribution. There was no evidence for linkage disequilibrium, eithe...

By comparing the dimensions and DNA contents of normal rod-shaped Escherichia coli with those of mutants that grow as spheres or ellipsoids, we have determined that two parameters remain unchanged: the DNA/mass ratio and the average cell length (diameter, for spherical cells). In consequence, the average volumes and DNA contents of the spherical mutant cells are about four to six times greater ...

An average size chromomere of the polytene X chromosome of Drosophila melanogaster contains enough DNA in each haploid equivalent strand to code for 30 genes, each 1,000 nucleotides long. We have attempted to learn about the organization of chromosomes by asking how many functional units can be localized within a chromomere. This was done by 1) recovery of mutants representative of every cistro...

It has been generally accepted that the TATA binding protein (TBP) is a universal mediator of transcription by RNA polymerase I, II, and III. Here we report that the TBP-related factor TRF1 rather than TBP is responsible for RNA polymerase III transcription in Drosophila. Immunoprecipitation and in vitro transcription assays using immunodepleted extracts supplemented with recombinant proteins r...