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Thesis Defense Announcement To: the George Mason Community > > *Jessica L. Keating > Master of Science in Biology > Molecular Biology concentration > * > Date: Tuesday December 1, 2009 > Time: 10:00 a.m. - 12:00 Noon > Place: Discovery Hall, Room 224 > Prince William campus > > Thesis Chair: Dr. Karl Fryxell, MMB Dept. > > *Title:* Mapping of the 1(3)DTS4 Gene and Analysis of its Role in the > Notch Pathway _//_ > *Abstract:* > l(3)DTS4 is an ethyl methanesulfonate (EMS) directed mutation that > exhibits temperature sensitive dominant lethality and is one of the > only mutations that expresses conditional dominant lethality in one > dose in triploids (HOLDEN and SUZUKI 1973). l(3)DTS4 is of particular > note, not only because it is a dominant temperature sensitive lethal > mutation, but also because our lab has shown it to have an > unexpectedly dramatic interaction with two different Notch (N) > alleles: N55e11 and N60g11 (JORDAN 2005). N55e11 /l(3)DTS4 and N60g11 > /l(3)DTS4 heterozygotes showed significantly reduced wing > notching in comparison to internal (N55e11 or N60g11/TM3, Sb) controls > (JORDAN 2005). A single copy of l(3)DTS4 was sufficient to > significantly prevent the wing notching caused by either Notch allele > at the permissive temperature for l(3)DTS4. This indicates that > l(3)DTS4 plays a key role in the development of the outer wing margin, > and its probable involvement in the Notch signaling cascade that > regulates this type of cell differentiation.The goal of this project > was to map and identify the gene(s) disrupted by the l(3)DTS4 mutation > and to further understand their role in the Notch processes that > determine outer wing growth. To this aim, complementation testing was > used in order to create a deletion map indicating regions of possible > interest. Two deletions, Df(3L)ZP1 and Df(3L)BSC113 were found to be > non complementary to l(3)DTS4. That is, l(3)DTS4/Df(3L)ZP1 and > l(3)DTS4/Df(3L)BSC113 heterozygotes had 100% fatality at all three > tested temperatures. Together with polytene chromosome analysis, the > complementation testing indicated that l(3)DTS4 resides within a > region from 67B3 -- 67B5. Additionally, qualitative analyses were > conducted in order to better understand the behavior of l(3)DTS4. Its > effect on Serrate and dally were analyzed, and the development of > l(3)DTS4 homozygous embryos was also examined. > > *All members of the George Mason University community are invited to > attend.* >