Squid and lark interaction during Drosophila oogenesis

Abstract

Drosophila melanogaster is used as a model organism to study the spatial and temporal regulation of gene expression. During oogenesis, proteins are produced and located in specific regions in order to develop a viable embryo and egg. Incorrect expression of the proteins results in non-viable eggs and embryos. Gurken (Grk) protein is required for the production of the dorsal appendages on Drosophila eggs and the dorsal-ventral patterning of the embryo. grk mRNA is tightly localized to the dorsal-anterior corner of the oocyte during the late stages of oogenesis. grk mRNA that is not localized to the dorsal-anterior of the oocyte, is not translated. An RNA-binding protein, Squid (Sqd), functions as a translational repressor grk. sqd mutants show a phenotypic defect in dorsal appendages because grk is over-translated, resulting in dorsalized eggs. In a previous study, a yeast two-hybrid screen identified an RNA-binding protein, Lark, that physically interacts with Sqd. Past investigations have indicated Lark participates in circadian rhythms, actin cytoskeletal organization and protein localization within the oocyte. Because Lark and Sqd have a physical interaction, we question if this interaction also has a biological function. The objective of this project is to investigate Lark’s role in the regulation of grk mRNA or protein, or if Lark cooperates with Sqd in other processes during oogenesis.