The number of essential telomerase components in the active ribonucleoprotein (RNP) has important implications for its mechanism of action yet is by and large unknown. We report that two differentially tagged TLC1 RNAs endogenously expressed in a heterozygous diploid and simultaneously detected via multi-color fluorescence in situ hybridization (FISH) experiments do not co-localize. Probabilistic calculations combined with direct quantification of FISH signals demonstrate that the TLC1 RNA indeed occurs as a single molecule in these RNPs. In addition, two differentially tagged reverse-transcriptase subunits could not be co-immunoprecipitated. These results therefore show that, in yeast cells, telomerase is assembled and matured and occurs as a monomer when not on telomeres. Finally, combining these findings with previous evidence leads us to propose that the enzyme also acts as a monomer when elongating telomeres.
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http://dx.doi.org/10.1016/j.celrep.2015.06.045 | DOI Listing |
Int J Mol Sci
January 2025
Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD 20201, USA.
Brain ischemia causes disruption in cerebral blood flow and blood-brain barrier integrity, which are normally maintained by astrocyte endfeet. Emerging evidence points to dysregulation of the astrocyte translatome during ischemia, but its effects on the endfoot translatome are unknown. In this study, we aimed to investigate the early effects of ischemia on the astrocyte endfoot translatome in a rodent cerebral ischemia and reperfusion model of stroke.
View Article and Find Full Text PDFiScience
December 2024
Department of Anesthesiology, Yale School of Medicine, New Haven, CT 06510, USA.
Brain waste clearance from the interstitial fluid environment is challenging to measure, which has contributed to controversy regarding the significance of glymphatic transport impairment for neurodegenerative processes. Dynamic contrast enhanced MRI (DCE-MRI) with cerebrospinal fluid administration of Gd-tagged tracers is often used to assess glymphatic system function. We previously quantified glymphatic transport from DCE-MRI data utilizing regularized optimal mass transport (rOMT) analysis, however, information specific to glymphatic clearance was not directly derived.
View Article and Find Full Text PDFbioRxiv
December 2024
Cerebral Codes and Circuits Connectivity team, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University; Paris, France.
How are associative memories formed? Which cells represent a memory, and when are they engaged? By visualizing and tagging cells based on their calcium influx with unparalleled temporal precision, we identified non-overlapping dorsal CA1 neuronal ensembles that are differentially active during associative fear memory acquisition. We dissected the acquisition experience into periods during which salient stimuli were presented or certain mouse behaviors occurred and found that cells associated with specific acquisition periods are sufficient alone to drive memory expression and contribute to fear engram formation. This study delineated the different identities of the cell ensembles active during learning, and revealed, for the first time, which ones form the core engram and are essential for memory formation and recall.
View Article and Find Full Text PDFMicrob Pathog
December 2024
Department of Urology, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, China. Electronic address:
The presence of the Hepatitis B virus (HBV) is considered as a valuable risk factor of hepatocellular carcinoma (HCC). To more deeply comprehend the molecular mechanism and transcriptome of HBV-induced HCC, we utilized tandem mass tagging (TMT)-based quantitative proteomics analysis and whole-transcriptome sequencing to analyze three sets of matched HepG2 hepatoma cells and HBV-positive HepAD38 cells. The differentially expressed (DE) proteins (1596), mRNAs (5263), miRNAs (581), lncRNAs (2672) and circRNAs (222) were subjected to differential expression and enrichment analyses in order to thoroughly assess the gene-regulatory circuits of HBV-induced HCC.
View Article and Find Full Text PDFVis Neurosci
December 2024
Stanford University, Department of Psychology Stanford, CA, USA.
Recent reports suggest the ON and OFF pathways are differentially susceptible to selective vision loss in glaucoma. Thus, perimetric assessment of ON- and OFF-pathway function may serve as a useful diagnostic. However, this necessitates a developed understanding of normal ON/OFF pathway function around the visual field and as a function of input intensity.
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