Abstracts

Germ cells and gametogenesis

Program/Abstract # 86Identification of amino acids in the Tre1 G protein-coupledreceptor important for cell migration and programmed cell deathMargaret M. Pruitt, Angela R. Kamps, Clark R. CoffmanDepartment of Genetics, Development and Cell Biology, USA

Germ cell development in Drosophila melanogaster is an excellentsystem to study cell migration and programmed cell death. Drosophilagerm cells are formed at a location distant from the presumptivegonad, requiring them to migrate to that location. The scattershot lossof function allele of tre1 displays a severe germ cell migration andprogrammed cell death phenotype. Instead of forming two gonads,the germ cells scatter across the posterior half of the embryo. Tre1 is aG protein-coupled receptor that has been shown to be involved inDrosophila germ cell migration. The molecular lesion in tre1sctt wasidentified as a single base pair change resulting in the deletion ofeight amino acids, RYILIACH. Structure function analyses wereperformed to determine which of these eight amino acids is criticalfor germ cell migration.

doi:10.1016/j.ydbio.2009.05.106

Program/Abstract # 87Deciphering the mechanisms of Drosophila primordial germcell deathClark R. Coffman, Lisa D. GranthamDepartment of Genetics, Development and Cell Biology, Iowa StateUniversity, Ames, IA, USA

During development, the embryo is shaped by tightly regulatedprograms of cell death that eliminate supernumerary cells, damagedcells, or cells whose functions are no longer needed. The primordialgerm cells of Drosophila are a genetically tractable model forelucidating mechanisms of programmed cell death. In wild-typeDrosophila melanogaster embryos, the number of primordial germcells is reduced by half between 4 and 9 h of development, a timebefore the germ cells have a close association with somatic gonadprecursor cells. Genetic screens have identified a few of the molecularcomponents of the germ cell death machinery, but our understandingof this process is extremely limited, and the fundamental mechan-isms of how these cells die are unknown. Previous work from our laband others reveals that there is no zygotic requirement for genesinvolved in canonical caspase-mediated cell death. In order toidentify additional components of these germ cell death networks,

we are screening for both maternally and zygotically supplied geneproducts that are required for normal germ cell death. We arecoupling these screens with imaging of germ cells in living embryosusing various molecular markers for different modes of cell death inorder to determine if the cells are dying via apoptosis, autophagy, orsome other means.

doi:10.1016/j.ydbio.2009.05.107

Program/Abstract # 88FACS-RNAi screening identifies new mel-28 genetic interactors inC. elegansAnita G. Fernandeza,b, Emily Misb, Fabio PianobaBiology Department, Fairfield University, Fairfield, CT, USAbCenter for Genomics and Systems Biology and Department of Biology,New York University, New York, NY, USA

MEL-28/ELYS is a large AT-hook protein required for nuclearenvelope integrity and chromosome segregation in metazoans. Asexpected by its fundamental function, MEL-28 is ubiquitouslyexpressed in all cells analyzed. However, mutations in the mel-28gene are maternal-effect, causing embryonic lethality in the progenyof homozygous mutant mothers that are otherwise wild-type.Therefore, the function of MEL-28 in most cells is predicted to bebuffered by other molecules. To identify additional proteins workingwith MEL-28 we looked for synthetic phenotypes in mel-28homozygous animals using RNAi. The challenge in this type of screenis to collect large numbers of homozygous animals. To accomplishthis in high throughput, we generated a strain with themel-28(t1684)mutation balanced by a GFP-marked chromosome and used afluorescence-activated cell sorter (FACS) to isolate non-fluorescentmel-28 homozygous larvae. We subjected themel-28 larvae to RNAi in96-well plates and recorded results by high-throughput digitalimaging. We present here the results from screening the genesencoded on Chromosome I. Of the 2260 clones tested, we found 14that are synthetic sterile with mel-28. Among these we found genesencoding components of expected molecular complexes such asnucleoporins. In addition, we found other classes of proteins, likehistones, suggesting new molecular connections between MEL-28and chromatin organization. Our results also show that FACS-RNAiscreening is a powerful way to uncover tissue-specific roles forpleiotropic genes.

doi:10.1016/j.ydbio.2009.05.108

Developmental Biology 331 (2009) 417–419

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