LSD1 regulates transposable elements

Determination of tissue size depends on the proper response of cells to a wide array of external and internal signals. Chromatin acts as a platform/substrate of signal integration and storage. Signal transduction pathways converge upon chromatin modifying enzymes and transcription factors to reprogram gene expression. However, little is known about the role of chromatin modifying factors in determining tissue size. Here, we show that loss of function of the histone demethylase dLSD1 results in a significant reduction of Drosophila wing size due to a decreased cell number. We show that dLSD1 depletion affects proliferation and induces DNA damage in larval wing imaginal discs. Through transcriptomics analysis, we find that dLSD1 controls the expression of multiple gene networks in wing imaginal discs. We then show that normal dLsd1 function contributes to repressing Transposable Element (TE) transcription and mobility. Additionally, our results suggest that increased TE mobility due to dLsd1 depletion contributes directly to altered organ size.