The goal of the proposed experiments is to understand how two cloned sequences, which exhibit a maternal-specific pattern of expression, function in early Drosophila development. These sequences were chosen from a group of maternal-specific sequences isolated in a screen for genes active in early development based on their expression pattern and cytological localization in a region amenable to genetic analyses. The assumption is made that genes whose messages are present only in the oocyte and early embryo, prior to the onset of zygotic transcription, should be involved in processes specific to this time period, e.g., rapid nuclear division, cellularization, and determination of axis polarity and external segmentation pattern. A combination of molecular, histological and genetic techniques will be used to answer the following specific questions: 1) What is the effect of mutation in the sequence? (maternal-effect lethality?) 2) What is the spatial location of maternal transcript through oogenesis and early embryogenesis and how does it relate to the blastoderm fate map? 3) What is the sequence of a cDNA clone homologous to the maternal transcript? 4) What is the temporal and spatial distribution of the proteins encoded by the maternal RNAs? This proposal is a direct approach to the molecular and genetic analysis of a developmentally important class of genes. The experiments described here will provide information for an understanding of the role of these genes in early embryonic development.
