http://blumberg-lab.bio.uci.edu/reprints/mango-cell-intro.pdf

The nuclear receptor superfamily: the second decade.

PERSPECTIVES AND SUMMARY . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210 ORIGINS OF CONSERVED GENE REGULATORS . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . 211 Steroids . . . . .. . . . . . . . . . . . . . . . . . . . .. . . .. . . . . . . . . . . . .. . . . . .. . . . . . . . . . . . . . .... . . . . . . .. . . . . . . . .. . . . . . . .. . 211 Steroid Receptors .... " . . . . . . . . . . . . . . . . . . . . . " . . . . . . . . . . . . . . . . . . . . . . . . "" . . . . . . . . . . . . . . . . . . . . . . " 211 FUNCTIONAL ASPECTS OF RECEPTOR STRUCTURE" . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213 Activation and Intracellular Localization ... . ". . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213 Steroid Binding .. ...... , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . " . . . . . . . . . . . . . . . . . . , 214 Nonspecific DNA Binding . .. . ..... ....... . ....... " . . . . . . . . .. . . . . . . . . . . . . . . . . " 215 Functional Heterogeneity 216 SELECTIVE RECEPTOR:DNA INTERACTIONS ... . . .... .. .... . .... . 21 7 Receptor Binding at Genomic Sites of Action . " . . . . . . . " 218 Detection of Specific DNA Binding Sites """""",,, , , """""'" . . . . . . . . . . . . . . . . . . . . . . . 21 8 DNA Sequences Bound by Steroid Receptors .. . ......... . ..... . ..... . ..... . ... , 221 LOCALIZATION OF STEROID RESPONSE ELEMENTS (REs) . .... " . . . . . . . . . 222 Deletion Mapping .. . ..... ......... . ....... . " . . . . . . . . . . . . . . . . . . . . . ""." . . .... . . . 223 RE-Promoter Fusions .... ......... . " . . . . . . . . . . . . . . . . . ". . . . . . . . . . . . . . . . . . 223 In Vitro Mutagenesis" ...... . ........ ......... .. " . . . . . . . . . . . . . . . . . "" . . . . . . " . . . . . . . . . . . . . . . . " 224 TRANSCRIPTIONAL ENHANCEMENT BY RECEPTOR:RE COMPLEXES " " "'" ' ' 224 Glucocorticoid-Dependent Enhancement 225 Detection and Characterization of Enhancers. . .. . . . . . . .... . . .... . . . . . . .. . . . . . . .... . . ... . . . . 225 EFFECTS OF RECEPTOR BINDING ON GENOME STRUCTURE ... " . . ". . . . . . . . . . . . . . 227 Cytological and Nuclease Probes .. . . """""" . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . " . . . . . . . . . 227 Chromosomal Protein Alterations 229 DNA-Structure Alterations 230 New Experimental Approaches . . . . . ... """ . . ,, .. " . . . . ,,". . . . . . . . . . . . . . . . . . . . . . . . . 232 HIGHER-ORDER CONTROL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . .. 233 Gene Networks ..... ...... ........ ....... . " . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ". . . . . . . . . 234 Multifactor Regulation ...... ... ,. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235

Steroid Receptor Regulated Transcription of Specific Genes and Gene Networks

Ten percent digestion of isolated nuclei by pancreatic deoxyribonuclease I preferentially removes globin DNA sequences from nuclei obtained from chick red blood cells but not from nuclei obtained from fibroblasts, from brain, or from a population of red blood cell precursors. Moreover, the nontranscribed ovalbumin sequences in nuclei isolated from red blood cells and fibroblasts are retained after mild deoxyribonuclease I digestion. This suggests that active genes are preferentially digested by deoxyribonuclease I. In contrast, treatment of red cell nuclei with staphylococcal nuclease results in no preferential digestion of active globin genes. When the 11S monomers obtained after staphylococcal nuclease digestion of nuclei are then digested with deoxyribonuclease I, the active globin genes are again preferentially digested. The results indicate that active genes are probably associated with histones in a subunit conformation in which the associated DNA is particularly sensitive to digestion by deoxyribonuclease I.

Chromosomal subunits in active genes have an altered conformation

In a search for embryonic lethal mutants on the second chromosome ofDrosophila melanogaster, 5764 balanced lines isogenic for an ethyl methane sulfonate (EMS)-treatedcn bw sp chromosome were established. Of these lines, 4217 carried one or more newly induced lethal mutations corresponding to a total of 7600 lethal hits. Eggs were collected from lethal-bearing lines and unhatched embryos from the lines in which 25% or more of the embryos did not hatch (2843 lines) were dechorionated, fixed, cleared and scored under the compound microscope for abnormalities of the larval cuticle. A total of 272 mutants were isolated with phenotypes unequivocally distinguishable from wild-type embryos on the basis of the cuticular pattern. In complementation tests performed between mutants with similar phenotype, 48 loci were identified by more than one allele, the average being 5.4 alleles per locus. Complementation of all other mutants was shown by 13 mutants. Members of the complementation groups were mapped by recombination analysis. No clustering of loci with similar phenotypes was apparent. From the distribution of the allele frequencies and the rate of discovery of new loci, it was estimated that the 61 loci represent the majority of embryonic lethal loci on the second chromosome yielding phenotypes recognizable in the larval cuticle.

Mutations affecting the pattern of the larval cuticle inDrosophila melanogaster : I. Zygotic loci on the second chromosome.

During metamorphosis of Drosophila melanogaster, a cascade of morphological changes is triggered by the steroid hormone 20-OH ecdysone via the ecdysone receptor, a member of the nuclear receptor superfamily. In this report, we have transferred insect hormone responsiveness to mammalian cells by the stable expression of a modified ecdysone receptor that regulates an optimized ecdysone responsive promoter. Inductions reaching 4 orders of magnitude have been achieved upon treatment with hormone. Transgenic mice expressing the modified ecdysone receptor can activate an integrated ecdysone responsive promoter upon administration of hormone. A comparison of tetracycline-based and ecdysone-based inducible systems reveals the ecdysone regulatory system exhibits lower basal activity and higher inducibility. Since ecdysone administration has no apparent effect on mammals, its use for regulating genes should be excellent for transient inducible expression of any gene in transgenic mice and for gene therapy.

https://www.pnas.org/content/pnas/93/8/3346.full.pdf

Ecdysone-inducible gene expression in mammalian cells and transgenic mice.

Temporal control of puffing activity in polytene chromosomes.

The radioimmune assay of ecdysteroid titres in drosophila melanogaster

Drosophila: the genetics of two major larval proteins

Sequential gene activation by ecdysone in polytene chromosomes of Drosophila melanogaster. VI. Inhibition by juvenile hormones.

A photo-map of the polytene chromosomes of fat body nuclei from third instar larvae ofDrosophila melanogaster has been constructed and keyed to the revised salivary gland maps of Bridges (1938), Bridges and Bridges (1939) and Bridges (1941a, b, 1942). Apparent variations in banding pattern are discussed in the light of current studies on polytene chromosome structure and function.

Geoff Richards

Papers

Temporal control of puffing activity in polytene chromosomes.

The radioimmune assay of ecdysteroid titres in drosophila melanogaster

Drosophila: the genetics of two major larval proteins

Sequential gene activation by ecdysone in polytene chromosomes of Drosophila melanogaster. VI. Inhibition by juvenile hormones.

The polytene chromosomes in the fat body nuclei ofDrosophila melanogaster