Project description:Transcription factors can affect autophagy activity by promoting or inhibiting the expression of autophagy and lysosomal related genes. As a zinc finger family DNA-binding protein, ZKSCAN3 has been reported to function as a transcriptional repressor of autophagy, silencing of which can induced autophagy and promoted lysosome biogenesis in cancer cells. However, the studies in Zkscan 3 knockout mice showed that the deficiency of Zkscan3 did not induce autophagy and in-crease lysosome biogenesis. In order to further explore the role of ZKSCAN3 in the transcriptional regulation of autophagy in human cells, we generated ZKSCAN3 knockout HK-2 and Hela cells by CRISPR/Cas9 system and analyzed the differences in gene expression between ZKSCAN3 deleted cells and non-deleted cells through fluorescence quantitative PCR, Western blot and transcriptome sequencing, with special attention to the differences in gene expression of autophagy and lysosomal biogenesis. We found that ZKSCAN3 is not an essential regulator of autophagic or lysosomal gene expression, as the absence ZKSCAN3 had no significantly effect on the expression of autophagy or lysosomal genes.
Project description:Autophagy is an essential cellular process that maintains homeostasis by recycling damaged organelles and nutrients during development and cellular stress. ZKSCAN3 is the sole identified master transcriptional repressor of autophagy in human cell lines. How ZKSCAN3 achieves autophagy repression at the mechanistic or organismal level however still remains to be elucidated. Furthermore, Zkscan3 knockout mice display no discernable autophagy-related phenotypes, suggesting that there may be substantial differences in the regulation of autophagy between normal tissues and tumor cell lines. Here, we demonstrate that vertebrate ZKSCAN3 and Drosophila M1BP are functionally homologous transcription factors in autophagy repression. Expression of ZKSCAN3 in Drosophila prevents premature autophagy onset due to loss of M1BP function and conversely, M1BP expression in human cells can prevent starvation-induced autophagy due to loss of nuclear ZKSCAN3 function. In Drosophila ZKSCAN3 binds genome-wide to sequences targeted by M1BP and transcriptionally regulates the majority of M1BP-controlled genes, demonstrating the evolutionary conservation of the transcriptional repression of autophagy and allow the potential for transitioning the mechanisms, gene targets and plethora metabolic processes controlled by M1BP onto ZKSCAN3 and opens up Drosophila as a tool in studying the function of ZKSCAN3 in autophagy and tumourigenesis.