Molecular Mechanisms L (3) 03670 Genes In Drosophila Neural Stem Cells In The Asymmetric Division

Asymmetric division of stem cells accomplishes two missions:self-renewal and differentiation. Stem cells maintain their population by self-renewal and produce differentiated cells which ensure the diversity of structure and function of tissues and organs through differentiation. Drosophila neuroblasts, also called neural stem cells, have the characteristics of stem cells. And Drosophila melanogaster has many advantages as a model organism. Therefore, in recent years Drosophila neuroblasts have become an ideal model for asymmetric division study.Keeping the balance of stem cell self-renewal and differentiation is very important to normal growth and development of organisms. Uncontrolled proliferation of stem cells can lead to tumor; excessive differentiation or suppressing stem cell self-renewal results in depletion of stem cell pool, which influences the development. Therefore, stem cell asymmetric division is a highly precise process. It is known that the PAR complex, including PAR-3(Bazooka), PAR-6, atypical Protein Kinase C (aPKC), is associated with Drosophila neuroblasts’ polarity and segregation of cell fate determinants and regulates the self-renewal and the Gai/Pins/Mud complex is responsible for spindle orientation. However, the detailed molecular and genetic mechanism how to control the balance between self-renewal and differentiation is still largely unknown.Using GAL4-UAS system in fruit flies to express specific RNAi constructs to knock down the expressions of various genes, we have screened for genes involved in neuroblast asymmetric division. We identified lethal(3)03670(CG1715) as one of candidate genes which participated in neuroblasts self-renewal. lethal(3)03670was expressed in Drosophila neuroblasts. The homozygous mutants died in the2nd instar larval stage. The cell cycle progression was effected. The MARCM clone analyses indicated that the mutant clones contained significantly less cells than wild type ones. Based on these observations, I concluded that lethal(3)03670may regulate cell cycle process of neuroblasts to control the self-renewal in Drosophila.