Multiplex coherent anti-Stokes Raman scattering highlights state of chromatin condensation in CH region

Tiffany Guerenne-Del Ben,Zakaniaina Rajaofara,Hideaki Kano,Vincent Sol,Vincent Couderc,Jean-Michel Petit,Philippe Leproux

doi:10.1038/s41598-019-50453-0

Tiffany Guerenne-Del Ben, Zakaniaina Rajaofara + Show 5 more

Open Access

https://doi.org/10.1038/s41598-019-50453-0

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Journal: Scientific Reports	Publication Date: Sep 25, 2019
Citations: 23	License type: open-access

Affiliation: University of Limoges, University of Tsukuba

Abstract

Coherent Raman microscopy has become a powerful tool in label-free, non-destructive and fast cell imaging. Here we apply high spectral resolution multiplex coherent anti-Stokes Raman scattering (MCARS) microspectroscopy in the high wavenumber region to the study of the cell cycle. We show that heterochromatin - the condensed state of chromatin - can be visualised by means of the vibrational signature of proteins taking part in its condensation. Thus, we are able to identify chromosomes and their movement during mitosis, as well as structures like nucleoli and nuclear border in interphase. Furthermore, the specific organization of the endoplasmic reticulum during mitosis is highlighted. Finally, we stress that MCARS can reveal the biochemical impact of the fixative method at the cellular level. Beyond the study of the cell cycle, this work introduces a label-free imaging approach that enables the visualization of cellular processes where chromatin undergoes rearrangements.

Highlights

In the last two decades, Raman microspectroscopy has become a powerful tool in label-free cell imaging
Throughout the cell cycle, heterochromatin - the condensed state of chromatin - can be visualised in the CH3 stretching band by means of the vibrational signature of proteins that take part in its condensation
Another strategy consists in focusing on proteins, which are the main component of heterochromatin

Summary

Introduction

In the last two decades, Raman microspectroscopy has become a powerful tool in label-free cell imaging. In order to generate the resonant CARS signal over the full range of Raman shifts (roughly 500–3500 cm−1, including both the fingerprint, CH and OH stretching regions) simultaneously, it is necessary to use a Stokes wave having a very broad spectrum at wavelengths longer than that of the pump. Such radiation can be obtained by generating a supercontinuum in a photonic crystal fibre (PCF)[16]. These configurations can provide rich vibrational information from biological samples

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