Genetics Commons^™

Evolution Acts On Enhancer Organization To Fine-Tune Gradient Threshold Readouts, Justin Crocker, Yoichiro Tamori, Albert Erives

Dartmouth Scholarship

The elucidation of principles governing evolution of gene regulatory sequence is critical to the study of metazoan diversification. We are therefore exploring the structure and organizational constraints of regulatory sequences by studying functionally equivalent cis-regulatory modules (CRMs) that have been evolving in parallel across several loci. Such an independent dataset allows a multi-locus study that is not hampered by nonfunctional or constrained homology. The neurogenic ectoderm enhancers (NEEs) of Drosophila melanogaster are one such class of coordinately regulated CRMs. The NEEs share a common organization of binding sites and as a set would be useful to study the relationship …

Expression Of Thor Does Not Increase Desiccation Resistance In Drosophila Melanogaster, Robert L. Kobey, Deborah K. Hoshizaki, Allen G. Gibbs

Undergraduate Research Opportunities Program (UROP)

Using microarray analysis of Drosophila melanogaster, the Gibbs lab has identified several hundred candidate genes that may be involved in desiccation resistance. One of these genes is Thor, an important downstream target of the TOR/insulin signaling pathway. Preliminary results confirm that Thor plays a role in desiccation resistance. Further research will be needed to verify these results and understand the mechanism by which Thor increases desiccation resistance. This research will also serve as a proof-of-principle for testing microarray-derived hypotheses.

A previous microarray analysis found evidence that down-regulation of protein synthesis might be a cellular response to desiccation through the up-regulation …

Coordinated Regulation Of Myc Trans-Activation Targets By Polycomb And The Trithorax Group Protein Ash1, Julie M. Goodliffe, Michael D. Cole, Eric Wieschaus

Dartmouth Scholarship

The Myc oncoprotein is a transcriptional regulator whose function is essential for normal development. Myc is capable of binding to 10% of the mammalian genome, and it is unclear how a developing embryo controls the DNA binding of its abundant Myc proteins in order to avoid Myc's potential for inducing tumorigenesis.To identify chromatin binding proteins with a potential role in controlling Myc activity, we established a genetic assay for dMyc activity in Drosophila. We conducted a genome-wide screen using this assay, and identified the Trithorax Group protein Ash1 as a modifier of dMyc activity. Ash1 is a histone methyltransferase known …

Ecdysteroid Titers In Mated And Unmated Drosophila Melanogaster Females, Lawrence G. Harshman, Anne M. Loeb, Beth A. Johnson

Lawrence G. Harshman Publications

Radioimmunoassay was used to determine ecdysteroid titers in mated or unmated Drosophila melanogaster females. Whole-body ecdysteroid titers increase after mating and this response is more pronounced after 12–24 hours than it is immediately after mating. In one experiment, females were mated to transgenic males deficient in accessory gland proteins to test whether these peptides mediate the observed increase in female whole-body ecdysteroid titers. Females mated to such transgenic males do not show a pronounced increase in whole-body ecdysteroid titers. The effect of mating on female hemolymph ecdysteroid titers was also investigated. Hemolymph ecdysteroid titers decrease after mating. The ecdysteroid titer …

Synthesis Of Low Molecular Weight Heat Shock Peptides Stimulated By Ecdysterone In A Cultured Drosophila Cell Line., Robert C. Ireland, Edward M. Berger

Dartmouth Scholarship

Treatment of Schneider's line 3 Drosophila cells with the steroid hormone ecdysterone rapidly stimulated the synthesis and accumulation of the polypeptide previously designated p7 [Berger, E. M., Ireland, R. C. & Wyss, C. (1980) Somatic Cell Genet. 6, 119-129]. In this report, p7 is identified as the 23,000-dalton heat shock polypeptide (hsp23). In addition to hsp23, the synthesis of the low molecular weight heat shock polypeptides hsp22, hsp26, and hsp27 was also stimulated by ecdysterone, although to different extents. Hybridization of a nick-translated genomic clone containing the hsp23 gene to a total RNA blot showed that ecdysterone stimulation of hsp23 …

An Electron Microscopic Examination Of Spermiogenesis In The Recessive Sex-Linked Male-Sterile Mutant, Ms(1)10s Of Drosophila Melanogaster, Lizabeth A. Perkins

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Electron microscopy of the testes of mutant ms(1)10S of Drosophila melanogaster is characterized by three major defects in the tail region of the developing spermatid. One is the apparent lack of paracrystalline body formation. The second is the loss of the primary derivative as development proceeds, and the third is the breakup and incorporation of the plasma membrane and periaxonemal sheath into membranous whorls. The mutant shows different patterns of axonemal breakup depending on the stage of differentiation in which degeneration begins. Degeneration continues until only cellular debris, scattered axonemal profiles and membranous whorls are all that are seen …

Modification Of Ontogenic Expression Due To Relocation Of The Ry+ Gene In Drosophila Melanogaster, Allen A. Badgett Jr.

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The ry⁺ gene of Drosophila melanogaster and its associated enzyme, xanthine dehydrogenase, were employed in an analysis of the relationship between regulation and the location of a gene in the genome. Enzyme assays as an indication of gene activity were performed on genotypes containing zero, one and two doses of ry⁺ genes. Xanthine dehydrogenase activity of rosy genes in normal and relocated positions was determined during development.

The results indicate: 1) the gene ry⁺ is differentially active during ontogeny; 2) the activity during ontogeny is proportional to the number of ry⁺ genes present in the genome; …