Functional Dissection Of MicroRNA In The Development Of Drosophila Larval Gonad

Femal Drosophila can keep their reproductive ability lifetime,this is due to the normal function of gernmline stem cells.Primordial germ cells(PGCs)are the germline stem cell precursors.The PGCs in larval gonads undergo a unique developmental process,which involves a regulatory pattern of cell fate and behavior.Apart from germcell lineage,Drosophila larva gonad also contains somatic cell lineage which will form several distinct somatic cell types including terminal filament cells and intermingled cells.These two somatic cell types act as PGC “niche” and play an important role in regulating the fate of PGCs.MicroRNAs are small(approximately 19-23 nucleotides)and noncoding RNAs that act as post-transcriptional regulators of gene expression.MiRNAs participate in the regulation of many biological processes like cell proliferation,apotosis,cell fate determination,differentiation etc.To systematically unravel the roles of miRNAs in PGC fate regulation,we performed a miRNA expression profiling on developing larval gonads in female flies.The analysis identified a group of miRNAs expressing in the tissues.We next examined if those miRNA candidates function in the developmental process via the Gal4/UAS binary system.We classify these miRNA candidates into four categories: miRNAs that affect TF morphogenesis and PGC differentiation,like miR-33 and miR-278;miRNAs that affect TF morphogenesis but not PGC differentiation,such as miR-14,miR-184,miR-263 a,miR-263 b and miR-276b;miRNA that affects PGC differentiation but not TF morphogenesis;miRNAs that do not affect TF morphogenesis and PGC differentiation,like let-7,miR-8 etc.The study in this paper provides a good working system for exploring functional miRNAs in the developmental contexts.