Grant: Operating Grant

Stem cells are essential for animal development and allow the maintenance and regeneration of tissues. Stem cells have the ability to divide and to develop into many types of adult cells throughout the lifetime of an organism. A key feature of stem cells is that they can divide to generate either new stem cells or new differentiated cells. In the testes and ovaries interactions between germline stem cells (GSCs) and their surrounding somatic cells play an essential role in regulating GSC function. Abnormal regulation of stem cells in the testes and ovaries give rise to tumor formation. Our long-term interest is in studying the mechanisms that underlie germline-soma communication and how these mechanisms act to regulate GSC differentiation and proliferation. The proposal focuses on the role of the two types of proteins in some-germline communication: those that regulate cell shape ('cytoskeletal regulators') and those that mediate the passage of biological signals between cells ('gap junction proteins'). We have two hypotheses: (i)Direct contact between soma and GSC is essential for their communication and consequently for GSC function. We propose that cytoskeletal regulators have an essential role in the formation of direct contacts between the soma and GSCs. (ii)We propose that biological signals that pass through gap junctions between soma and germline have an essential role in regulating GSC function. Using genetic screens in the fruit fly we will identify and characterize cytoskeletal regulator and gap-junction proteins that are required for soma-GSC communication and stem cell function. We will use flies carrying mutations in the genes that encode cytoskeletal regulators and gap junction proteins to deplete these proteins in the testes and study the resulting effects on GSC function. By investigating soma-GSC communication our work provides insight into the biology of germline tumours and the mechanisms of sperm production.