Mapping of the l(3)DTS4 Gene and Analysis of its Role in the Notch Pathway




Keating, Jessica

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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: N^55e11 and N^60g11 (JORDAN 2005). N^55e11 /l(3)DTS4 and N^60g11 /l(3)DTS4 heterozygotes showed significantly reduced wing notching in comparison to internal (N^55e11 or N^60g11 /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.



Drosophila, Notch, Polytene, Lethality