title: E2fl1 is a meiosis-specific transcription factor in the protist Tetrahymena thermophila.
abstract: Members of the E2F family of transcription factors have been reported to regulate the expression of genes involved in cell cycle control, DNA replication, and DNA repair in multicellular eukaryotes. Here, E2FL1, a meiosis-specific E2F transcription factor gene, was identified in the model ciliate Tetrahymena thermophila. Loss of this gene resulted in meiotic arrest prior to anaphase I. The cytological experiments revealed that the meiotic homologous pairing was not affected in the absence of E2FL1, but the paired homologous chromosomes did not separate and assumed a peculiar tandem arrangement. This is the first time that an E2F family member has been shown to regulate meiotic events. Moreover, BrdU incorporation showed that DSB processing during meiosis was abnormal upon the deletion of E2FL1. Transcriptome sequencing analysis revealed that E2FL1 knockout decreased the expression of genes involved in DNA replication and DNA repair in T. thermophila, suggesting that the function of E2F is highly conserved in eukaryotes. In addition, E2FL1 deletion inhibited the expression of related homologous chromosome segregation genes in T. thermophila. The result may explain the meiotic arrest phenotype at anaphase I. Finally, by searching for E2F DNA-binding motifs in the entire T. thermophila genome, we identified 714 genes containing at least one E2F DNA-binding motif; of these, 235 downregulated represent putative E2FL1 target genes.
authors.affiliation: a Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences , Wuhan , People's Republic of China.|b University of Chinese Academy of Sciences , Beijing , People's Republic of China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.affiliation: a Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences , Wuhan , People's Republic of China.|c Department of Chromosome Biology and Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna , Vienna , Austria.
authors.forename: Miao
authors.initials: M
authors.lastname: Tian
authors.affiliation: a Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences , Wuhan , People's Republic of China.|b University of Chinese Academy of Sciences , Beijing , People's Republic of China.
authors.forename: Guan-Xiong
authors.initials: GX
authors.lastname: Yan
authors.affiliation: c Department of Chromosome Biology and Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna , Vienna , Austria.
authors.forename: Anura
authors.initials: A
authors.lastname: Shodhan
authors.affiliation: a Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences , Wuhan , People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Miao
mesh_terms: D000705:Anaphase; D020090:Chromosome Segregation / Q000235:genetics; D004247:DNA / Q000378:metabolism; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair / Q000235:genetics; D015536:Down-Regulation / Q000235:genetics; D020869:Gene Expression Profiling; D059765:Homologous Recombination / Q000235:genetics; D008540:Meiosis / Q000235:genetics*; D009154:Mutation / Q000235:genetics; D059372:Nucleotide Motifs / Q000235:genetics; D010641:Phenotype; D015800:Protozoan Proteins / Q000378:metabolism*; D012098:Reproduction / Q000235:genetics; D016808:Tetrahymena thermophila / Q000166:cytology* / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D015800:Protozoan Proteins; D014157:Transcription Factors; D004247:DNA
keywords: DNA repair; Tetrahymena thermophila; chromosome segregation; meiosis; transcription factor