C. elegans GLP-1/Notch activates transcription in a probability gradient across the germline stem cell pool

• Published in: eLife Vol. 5
• Main Authors: Lee, ChangHwan, Sorensen, Erika B, Lynch, Tina R, Kimble, Judith
• Format: Journal Article
• Language: English
• Published: England eLife Sciences Publications Ltd 05.10.2016; eLife Sciences Publications, Ltd
• Subjects: active transcription site; Animals; Caenorhabditis elegans - embryology; Caenorhabditis elegans - physiology; Caenorhabditis elegans Proteins - metabolism; Cell Biology; Cell cycle; Cytoplasm; Developmental Biology and Stem Cells; Embryonic Germ Cells - physiology; Fluorescence in situ hybridization; Homeostasis; In Situ Hybridization, Fluorescence; lst-1; Mesenchyme; Notch protein; Nuclei; Quantitation; Receptors, Notch - metabolism; Single Molecule Imaging; single-molecule FISH; Stem cells; Stem Cells - physiology; sygl-1; Transcription activation; Transcription, Genetic; Zebrafish; stem cells; C. elegans; cell biology; single-molecule FISH; developmental biology; lst-1; sygl-1; active transcription site
• ISSN: 2050-084X; 2050-084X
• DOI: 10.7554/eLife.18370

Notch signaling maintains a pool of germline stem cells within their single-celled mesenchymal niche. Here we investigate the Notch transcriptional response in germline stem cells using single-molecule fluorescence hybridization coupled with automated, high-throughput quantitation. This approach allows us to distinguish Notch-dependent nascent transcripts in the nucleus from mature mRNAs in the cytoplasm. We find that Notch-dependent active transcription sites occur in a probabilistic fashion and, unexpectedly, do so in a steep gradient across the stem cell pool. Yet these graded nuclear sites create a nearly uniform field of mRNAs that extends beyond the region of transcriptional activation. Therefore, active transcription sites provide a precise view of where the Notch-dependent transcriptional complex is productively engaged. Our findings offer a new window into the Notch transcriptional response and demonstrate the importance of assaying nascent transcripts at active transcription sites as a readout for canonical signaling.