scholarly journals Gains of 12p13.31 delay WNT-mediated initiation of hPSC differentiation and promote residual pluripotency in a cell cycle dependent manner

2021 ◽  
Author(s):  
Alexander Keller ◽  
Yingnan Lei ◽  
Nuša Krivec ◽  
Edouard Couvreu De Deckersberg ◽  
Dominika Dziedzicka ◽  
...  

Though gains of chromosome 12p13.31 are highly recurrent in hPSC, their impact on differentiation is poorly understood. We identify a reduction in differentiation capacity towards all three germ layers and a subpopulation of residual pluripotent cells that appear during hepatic specification. These cells form as a result of the overexpression of NANOG and GDF3, whereby NANOG as the primary driver delays activation of WNT signaling, partly as a result of a direct physical interaction with TCF7. Entry into the residual state is determined by cell cycle position at the onset of differentiation and is maintained by a feedback loop between NANOG and GDF3. These findings highlight the ability of genetically abnormal hPSC to escape correct differentiation and to form residual pluripotent cells, an important risk in the safe clinical translation of hPSC. Our results further refine the molecular mechanisms that underpin the exit from pluripotency and onset of differentiation.

2019 ◽  
Vol 47 (16) ◽  
pp. 8439-8451 ◽  
Author(s):  
Alberto González-Medina ◽  
Elena Hidalgo ◽  
José Ayté

Abstract In fission yeast, MBF-dependent transcription is inactivated at the end of S phase through a negative feedback loop that involves the co-repressors, Yox1 and Nrm1. Although this repression system is well known, the molecular mechanisms involved in MBF activation remain largely unknown. Compacted chromatin constitutes a barrier to activators accessing promoters. Here, we show that chromatin regulation plays a key role in activating MBF-dependent transcription. Gcn5, a part of the SAGA complex, binds to MBF-regulated promoters through the MBF co-activator Rep2 in a cell cycle-dependent manner and in a reverse correlation to the binding of the MBF co-repressors, Nrm1 or Yox1. We propose that the co-repressors function as physical barriers to SAGA recruitment onto MBF promoters. We also show that Gcn5 acetylates specific lysine residues on histone H3 in a cell cycle-regulated manner. Furthermore, either in a gcn5 mutant or in a strain in which histone H3 is kept in an unacetylated form, MBF-dependent transcription is downregulated. In summary, Gcn5 is required for the full activation and correct timing of MBF-regulated gene transcription.


Author(s):  
Agnieszka T. Kawashima ◽  
Cassandra Wong ◽  
Gema Lordén ◽  
Charles C. King ◽  
Pablo Lara-Gonzalez ◽  
...  

PH domain Leucine-Rich Repeat Protein Phosphatase 1 (PHLPP1) is a tumor suppressor that directly dephosphorylates a wide array of substrates, most notably the pro-survival kinase Akt. However, little is known about the molecular mechanisms governing PHLPP1 itself. Here we report that PHLPP1 is dynamically regulated in a cell cycle-dependent manner, and deletion of PHLPP1 results in mitotic delays and increased rates of chromosomal segregation errors. We show that PHLPP1 is hyperphosphorylated during mitosis by Cdk1 in a functionally uncharacterized region known as the PHLPP1 N-terminal extension (NTE). A proximity-dependent biotin identification (BioID) interaction screen revealed that during mitosis PHLPP1 dissociates from plasma membrane scaffolds, such as Scribble, by a mechanism that depends on its NTE, and gains proximity with kinetochore and mitotic spindle proteins such as KNL1 and TPX2. Our data are consistent with a model in which phosphorylation of PHLPP1 during mitosis regulates binding to its mitotic partners and allows accurate progression through mitosis. The finding that PHLPP1 binds mitotic proteins in a cell cycle- and phosphorylation-dependent manner may have relevance to its tumor suppressive function.


2006 ◽  
Vol 16 (2) ◽  
pp. 199-209 ◽  
Author(s):  
Jean Schneikert ◽  
Annette Grohmann ◽  
Jürgen Behrens

2021 ◽  
Author(s):  
Yuting Liu ◽  
Kehui Wang ◽  
Li Huang ◽  
Jicheng Zhao ◽  
Xinpeng Chen ◽  
...  

Centromere identity is defined by nucleosomes containing CENP-A, a histone H3 variant. The deposition of CENP-A at centromeres is tightly regulated in a cell-cycle-dependent manner. We previously reported that the spatiotemporal control of centromeric CENP-A incorporation is mediated by the phosphorylation of CENP-A Ser68. However, a recent report argued that Ser68 phosphoregulation is dispensable for accurate CENP-A loading. Here, we report that the substitution of Ser68 of endogenous CENP-A with either Gln68 or Glu68 severely impairs CENP-A deposition and cell viability. We also find that mice harboring the corresponding mutations are lethal. Together, these results indicate that the dynamic phosphorylation of Ser68 ensures cell-cycle-dependent CENP-A deposition and cell viability.


2015 ◽  
Vol 11 (6) ◽  
pp. e1004971 ◽  
Author(s):  
Pierre Génin ◽  
Frédérique Cuvelier ◽  
Sandrine Lambin ◽  
Josina Côrte-Real Filipe ◽  
Elodie Autrusseau ◽  
...  

Blood ◽  
2000 ◽  
Vol 95 (12) ◽  
pp. 3970-3977 ◽  
Author(s):  
Michael C. Heinrich ◽  
Kirsten V. Silvey ◽  
Stacie Stone ◽  
Amy J. Zigler ◽  
Diana J. Griffith ◽  
...  

The Fanconi Anemia (FA) Group C complementation group gene (FANCC) encodes a protein, FANCC, with a predicted Mr of 63000 daltons. FANCC is found in both the cytoplasmic and the nuclear compartments and interacts with certain other FA complementation group proteins as well as with non-FA proteins. Despite intensive investigation, the biologic roles of FANCC and of the other cloned FA gene products (FANCA and FANCG) remain unknown. As an approach to understanding FANCC function, we have studied the molecular regulation of FANCC expression. We found that although FANCCmRNA levels are constant throughout the cell cycle, FANCC is expressed in a cell cycle-dependent manner, with the lowest levels seen in cells synchronized at the G1/S boundary and the highest levels in the M-phase. Cell cycle–dependent regulation occurred despite deletion of the 5′ and 3′ FANCC untranslated regions, indicating that information in the FANCC coding sequence is sufficient to mediate cell cycle–dependent regulation. Moreover, inhibitors of proteasome function blocked the observed regulation. We conclude that FANCC expression is controlled by posttranscriptional mechanisms that are proteasome dependent. Recent work has demonstrated that the functional activity of FA proteins requires the physical interaction of at least FANCA, FANCC, and FANCG, and possibly of other FA and non-FA proteins. Our observation of dynamic control of FANCC expression by the proteasome has important implications for understanding the molecular regulation of the multiprotein complex.


2004 ◽  
Vol 297 (1) ◽  
pp. 285-293 ◽  
Author(s):  
Noriko Yasuhara ◽  
Eri Takeda ◽  
Hitomi Inoue ◽  
Ippei Kotera ◽  
Yoshihiro Yoneda

2003 ◽  
Vol 8 (11) ◽  
pp. 889-896 ◽  
Author(s):  
Takayuki Hattori ◽  
Kyoko Kitagawa ◽  
Chiharu Uchida ◽  
Toshiaki Oda ◽  
Masatoshi Kitagawa

2003 ◽  
Vol 278 (30) ◽  
pp. 27421-27431 ◽  
Author(s):  
Christian Gaiddon ◽  
Maria Lokshin ◽  
Isabelle Gross ◽  
Danielle Levasseur ◽  
Yoichi Taya ◽  
...  

2003 ◽  
Vol 133 (1) ◽  
pp. 348-360 ◽  
Author(s):  
Frédéric Delmas ◽  
Johann Petit ◽  
Jérôme Joubès ◽  
Martial Séveno ◽  
Thomas Paccalet ◽  
...  

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