A semester-long project for teaching basic techniques in molecular biology such as restriction fragment length polymorphism analysis to undergraduate and graduate students.

Several reports on science education suggest that students at all levels learn better if they are immersed in a project that is long term, yielding results that require analysis and interpretation. I describe a 12-wk laboratory project suitable for upper-level undergraduates and first-year graduate students, in which the students molecularly locate and map a gene from Drosophila melanogaster called dusky and one of dusky's mutant alleles. The mapping strategy uses restriction fragment length polymorphism analysis; hence, students perform most of the basic techniques of molecular biology (DNA isolation, restriction enzyme digestion and mapping, plasmid vector subcloning, agarose and polyacrylamide gel electrophoresis, DNA labeling, and Southern hybridization) toward the single goal of characterizing dusky and the mutant allele dusky(73).

Apoptosis: a four-week laboratory investigation for advanced molecular and cellular biology students.

Over the past decade, apoptosis has emerged as an important field of study central to ongoing research in many diverse fields, from developmental biology to cancer research. Apoptosis proceeds by a highly coordinated series of events that includes enzyme activation, DNA fragmentation, and alterations in plasma membrane permeability. The detection of each of these phenotypic changes is accessible to advanced undergraduate cell and molecular biology students.

Molecular analysis of the Drosophila miniature-dusky ( m-dy) gene complex: m-dy mRNAs encode transmembrane proteins with similarity to C. elegans cuticulin.

Mutations in the Drosophila miniature-dusky ( m-dy) gene complex were first reported by Morgan and Bridges about 90 years ago. m-dy mutants have abnormally small wings, a phenotype attributed to a cell-autonomous reduction in the size of the epidermal cells comprising the differentiated wing. Using a molecular genetic approach, we have characterized the m-dy chromosomal interval and identified a pair of adjacent transcription units corresponding to m and dy.

Maintenance of the DNA puff expanded state is independent of active replication and transcription.

The maintenance of the expanded state of DNA puffs II/2B and II/9A in polytene chromosomes from stage 14 x 7 Sciara coprophila salivary glands was assayed after inhibition of RNA synthesis, DNA synthesis, or both processes together. Heat shock conditions were established in order to inhibit transcription. Polypeptides of Mr 72,000 and 36,000 were produced in Sciara after heat shock.

Developmental progression of DNA puffs in Sciara coprophila: amplification and transcription.

DNA amplification for two major DNA puffs (II/2B and II/9A) of the fungus fly Sciara coprophila increases steeply from 17 to 19 days after hatching (18 degrees C), resulting in almost 20-fold more DNA at these loci in mature larval salivary glands than in adult tissues. At 19 days after hatching when gene amplification reaches a plateau, there is a burst in the amount of mRNA encoded by these two DNA puffs. Expansion of the two puffs coincides with the increase in transcription rather than reinitiation of DNA replication.

A superfamily of Drosophila satellite related (SR) DNA repeats restricted to the X chromosome euchromatin.

The 1.688 g/cm3 class of Drosophila satellite DNA is predominantly localized to the centromeric heterochromatin of the X chromosome. We report here the existence of 1.

Mutational analysis of the Drosophila miniature-dusky (m-dy) locus: effects on cell size and circadian rhythms.

A mutational analysis has been performed to explore the function of the Drosophila melanogaster miniature-dusky (m-dy) locus. Mutations at this locus affect wing development, fertility and behavior. The genetic characterization of 13 different mutations suggests that m and dy variants are alleles of a single complex gene.

Molecular characterization of DNA puff II/9A genes in Sciara coprophila.

A cDNA clone, pSDII/9, that hybridizes in situ to ecdysone-regulated DNA puff II/9A in Sciara coprophila was used as a probe to isolate a Sciara genomic clone. lambda pSDII/9, which contains a 14.7 x 10(3) base-pair DNA insert.