Real-time imaging of transcriptional activation in live cells reveals rapid up-regulation of the cyclin-dependent kinase inhibitor gene CDKN1A in replicative cellular senescence
Authors: Wendy A Jobling
John M Sedivy
Utz Herbig
Annie Dutriaux
Wenyi Wei
Journal: Aging Cell (2008)
Discipline: MOLECULAR BIOLOGY & GENETICS
Keywords: Cellular replicative senescence; telomere shortening; p21(CIP1/WAF1); CDKN1A gene; cell cycle regulator
Affiliations: Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912, USA.

Abstract:  Cellular replicative senescence is a permanent growth arrest state that can be triggered by telomere shortening. The cyclin-dependent kinase (Cdk) inhibitor p21(CIP1/WAF1) (p21), encoded by the CDKN1A gene, is a critical cell cycle regulator whose expression increases as cells approach senescence. Although the pathways responsible for its up-regulation are not well understood, compelling evidence indicates that the upstream triggering event is telomere dysfunction. Studies of replicative senescence have been complicated by the asynchrony of its onset, which is caused by the continuous and stochastic variability in individual cell lifespans. In fact, the actual entry into senescence has never been observed in a single unperturbed cell. We report here a new in vitro human model system that allows entry into senescence to be monitored in real-time in individual viable cells. We used homologous recombination to generate non-immortalized fibroblast cells with the enhanced yellow fluorescence protein (EYFP) gene knocked into one CDKN1A gene copy, allowing promoter activity to be visualized as fluorescence intensity. Gamma irradiation, DNA-damaging drugs, expression of p14(ARF) or oncogenic Ras, and replicative exhaustion all resulted in elevated EYFP expression, demonstrating its proper control by physiological signalling circuits. Analysis by time-lapse microscopy of cultures approaching replicative senescence revealed that p21 levels rise abruptly in individual aging cells and remain elevated for extended periods of time. 

Retracted: No

PubPeer comments:
 This paper belongs to a set of over 400 papers (as per February 2020) that share very similar Western blots with tadpole-like shaped bands, the same background pattern, and striking similarities in title structures, paper layout, bar graph design, and - in a subset - flow cytometry panels. Despite these similarities, these papers are authored by researchers from different departments and institutes, with almost no overlap in authors. The list of these papers is available here: https: docs.google.com spreadsheets d 1KXqTAyl4j-jVorFPMD2XRpr76LcIKJ0CVyIvRj0exYQ edit?usp=sharing A more detailed description of this set of papers, suspected to all be generated by a common source, a paper mill , can be found here: * https: forbetterscience.com 2020 01 24 the-full-service-paper-mill-and-its-chinese-customers (January 2020) * https: scienceintegritydigest.com 2020 02 21 the-tadpole-paper-mill (February 2020) The same paper mill has been described in these papers: * Jana Christopher - Systematic fabrication of scientific images revealed - FEBS Letters (2018) - https: febs.onlinelibrary.wiley.com doi full 10.1002 1873-3468.13201 * Jennifer A Byrne and Jana Christopher - Digital magic, or the dark arts of the 21st centuryu2014how can journals and peer reviewers detect manuscripts and publications from paper mills? - FEBS Letters (2020) - https: febs.onlinelibrary.wiley.com doi full 10.1002 1873-3468.13747 , 
 Retraction, December 2021: https: www.medscimonit.com abstract full idArt 935766  This publication has been retracted by the Editor due to the identification of non-original figure images and manuscript content that raise concerns regarding the credibility and originality of the study and the manuscript. , 
 [Source: Jining First People s Hospital Release time: 2021-12-17] : In order to strengthen the construction of scientific research integrity, severely punish violations, and create a good environment for scientific and technological innovation, the relevant paper issues recently investigated and dealt with by this unit are hereby notified as follows. 8. Insulin Growth Factor 1 Protects Neural Stem Cells Against Apoptosis Induced by Hypoxia Through Akt Mitogen-Activated Protein Kinase Extracellular Signal-Regulated Kinase (Akt MAPK ERK) Pathway in Hypoxia-Ishchemic Encephalopathy , after investigation, it is an academic misconduct of tampering with data and fabricating the research process. The relevant responsible persons are dealt with as follows: Zheng Zebao (corresponding author, combined with the other two papers): Cancellation of the application qualifications for scientific research projects, scientific research awards, scientific and technological achievements, scientific and technological talent plans within 6 years; cancellation of 6 years as a nominee or recommender, Nominees or recommenders, review experts and other qualifications; cancel their membership or membership in academic institutions such as societies and associations; recover the author s personal research awards and honorary titles; revoke the higher-level majors that have been obtained Technical position; defer promotion to a higher-level professional technical position for 4 years; instruct to contact the magazine as soon as possible to withdraw the manuscript; administrative warning. Zhao Bing (first author, merged with another paper): Cancellation of application qualifications for scientific research projects, scientific research awards, scientific and technological achievements, scientific and technological talent plans within 6 years; cancellation of 6 years as a nominee or recommender, nominee or recommender, Review experts and other qualifications; cancel their membership or membership in academic institutions such as societies and associations; recover the author s personal research awards and honorary titles; revoke the higher-level professional and technical positions that have been obtained; recover scientific research Matching funds for project approval; deferment of promotion to a higher-level professional and technical position for 3 years; administrative warning. ,