%0 Journal Article %T Fine scale analysis of gene expression in Drosophila melanogaster gonads reveals Programmed cell death 4 promotes the differentiation of female germline stem cells %A Amy C Cash %A Justen Andrews %J BMC Developmental Biology %D 2012 %I BioMed Central %R 10.1186/1471-213x-12-4 %X Here we report a genome-wide expression study that uses laser cutting microdissection to isolate germline stem cells, somatic niche cells, and early differentiating germ cells from female and male gonads. Analysis of this data, in association with two previously published genome-wide GSC data sets, revealed sets of candidate genes as putatively expressed in specific cell populations. Investigation of one of these genes, CG10990 the Drosophila ortholog of mammalian Programmed cell death 4 (Pdcd4), reveals expression in female and male germline stem cells and early differentiating daughter cells. Functional analysis demonstrates that while it is not essential for oogenesis or spermatogenesis, it does function to promote the differentiation of GSCs in females. Furthermore, in females, Pdcd4 genetically interacts with the key differentiation gene bag of marbles (bam) and the stem cell renewal factor eIF4A, suggesting a possible pathway for its function in differentiation.We propose that Pdcd4 promotes the differentiation of GSC daughter cells by relieving the eIF4A-mediated inhibition of Bam.Stem cells are essential for embryonic development and tissue maintenance and repair. They have the ability to divide to produce cells that can retain stem cell identity (self-renewal) as well as cells that can differentiate into specialized cell types (differentiation). The balance between self-renewal and differentiation is critical. An excess of differentiation can lead to stem cell depletion and tissue senescence, whereas an excess of self-renewal, and/or a deficiency of differentiation, can lead to an accumulation of undifferentiated proliferative cells. The Drosophila germline is a well established model for the study of adult stem cells and the control of self-renewal and differentiation [1].Many stem cells depend on a specialized microenvironment, the stem cell niche. Drosophila germline stem cells are sexually dimorphic and exist in sexually dimorphic niches. Each ovary is %U http://www.biomedcentral.com/1471-213X/12/4