A new ultradian rhythm in mammalian cell dry mass observed by holography

Lamya Ghenim (1) , Cédric Allier (2) , Patricia Obeïd (3) , Lionel Hervé (2) , Jean-Yves Fortin (4) , Maxim Balakirev (5) , Xavier Gidrol (6)

1 IRIG - Institut de Recherche Interdisciplinaire de Grenoble
2 CEA-LETI - Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information
3 BGE - UMR S1038 - Laboratoire de Biologie à Grande Échelle
4 IJL - Institut Jean Lamour
5 BIOMICS - Biomicrotechnologie et génomique fonctionnelle
6 LEFG - Laboratoire d'Exploration Fonctionnelle des Génomes

We have discovered a new 4 hour ultradian rhythm that occurs during the interphase of the cell cycle in a wide range of individual mammalian cells, including both primary and transformed cells. The rhythm was detected by holographic lens-free microscopy that follows the histories of the dry mass of thousands of single live cells simultaneously, each at a resolution of five minutes. It was vital that the rhythm was observed in inherently heterogeneous cell populations, thus eliminating synchronization and labeling bias. The rhythm is independent of circadian rhythm, and is temperature-compensated. We show that the amplitude of the fundamental frequency provides a way to quantify the effects of, chemical reagents on cells, thus shedding light on its mechanism. The rhythm is suppressed by proteostasis disruptors and is detected only in proliferating cells, suggesting that it represents a massive degradation and re-synthesis of protein every 4 hours in growing cells.

Domaines: Sciences du Vivant [q-bio]; Physique [physics]

Lamya Ghenim, Cédric Allier, Patricia Obeïd, Lionel Hervé, Jean-Yves Fortin, et al.. A new ultradian rhythm in mammalian cell dry mass observed by holography. 2020. ⟨hal-03100163⟩