The Krüppel-like factor 9 cistrome in mouse hippocampal neurons reveals predominant transcriptional repression via proximal promoter binding

BMC Genomics

Research Article

Arasakumar Subramani¹  Joseph R. Knoedler²  Robert J. Denver³ 

[1] Department of Molecular, Cellular and Developmental Biology, The University of Michigan, 3065C Kraus Natural Science Building, 48109, Ann Arbor, MI, USA;Neuroscience Graduate Program, The University of Michigan, 48109, Ann Arbor, MI, USA;Current address: Department of Psychiatry and Behavioral Sciences, Stanford University, 94305, Stanford, CA, USA;Neuroscience Graduate Program, The University of Michigan, 48109, Ann Arbor, MI, USA;Department of Molecular, Cellular and Developmental Biology, The University of Michigan, 3065C Kraus Natural Science Building, 48109, Ann Arbor, MI, USA;

关键词: Klf9;    Chromatin;    Transcription;    Hippocampal neurons;   

DOI  :  10.1186/s12864-017-3640-7

 received in 2016-09-17, accepted in 2017-03-17,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundKrüppel-like factor 9 (Klf9) is a zinc finger transcription factor that functions in neural cell differentiation, but little is known about its genomic targets or mechanism of action in neurons.ResultsWe used the mouse hippocampus-derived neuronal cell line HT22 to identify genes regulated by Klf9, and we validated our findings in mouse hippocampus. We engineered HT22 cells to express a Klf9 transgene under control of the tetracycline repressor, and used RNA sequencing to identify genes modulated by Klf9. We found 217 genes repressed and 21 induced by Klf9. We also engineered HT22 cells to co-express biotin ligase and a Klf9 fusion protein containing an N-terminal biotin ligase recognition peptide. Using chromatin-streptavidin precipitation (ChSP) sequencing we identified 3,514 genomic regions where Klf9 associated. Seventy-five percent of these were within 1 kb of transcription start sites, and Klf9 associated in chromatin with 60% of the repressed genes. We analyzed the promoters of several repressed genes containing Klf9 ChSP peaks using transient transfection reporter assays and found that Klf9 repressed promoter activity, which was abolished after mutation of Sp/Klf-like motifs. Knockdown or knockout of Klf9 in HT22 cells caused dysregulation of Klf9 target genes. Chromatin immunoprecipitation assays showed that Klf9 associated in chromatin from mouse hippocampus with genes identified by ChSP sequencing on HT22 cells, and expression of Klf9 target genes was dysregulated in the hippocampus of neonatal Klf9-null mice. Gene ontology analysis revealed that Klf9 genomic targets include genes involved in cystokeletal remodeling, Wnt signaling and inflammation.ConclusionsWe have identified genomic targets of Klf9 in hippocampal neurons and created a foundation for future studies on how it functions in chromatin, and regulates neuronal morphology and survival across the lifespan.

【 授权许可】

CC BY   
© The Author(s). 2017