Life Sciences Research for Lifelong Health

Rachael Walker

Head of Flow Cytometry: Dr Rachael Walker
Building 580, Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT
rachael.walker@babraham.ac.uk
01223 496559

Rachael has over a dozen years of experience in flow cytometry and cell sorting and nearly 10 years of working in flow cytometry core facilities. Rachael joined the core in September 2012, following 7 years running Flow Cytometry Core Facilities at the University of Cambridge.

Rachael has extensive experience in analysis and sorting cells of differing types including; immunology, cell biology, stem cell biology, large cells such as cardiomyocytes, c. elegans eggs; organelles such as nuclei. Rachael can provide expertise in experimental setup, optimisation and analysis. She can help with optimal instrument set up, post-acquisition analysis of data and preparing figures for papers.

Education:
2005- PhD in Tissue Engineering, Department of Clinical Engineering, University of Liverpool
2001- BMedSc (Honours), Biomedical Materials Science, University of Birmingham

Flow Cytometry community
Rachael is very involved with the flow cytometry community on a local, national and international level.

Rachael’s work includes:
  • Awarded International Society for Advancement of Cytometry (ISAC) Scholarship 2012-2014
  • Awarded ISAC ‘Emerging Leader in Shared Resource Laboratory’ Scholarship 2014-2016
  • Co-chair of ISAC Membership Services Committee
  • Member of ISAC Program committee for CYTO conferences since 2010
  • Secretary and organiser of local Mid-Anglia Cytometry (MACC) meetings
  • Secretary of flowcytometryUK, also one of main organisers of flowcytometryUK national annual meetings
  • Fellow and Secretary of Royal Microscopical Society (RMS) Cytometry Section
  • Lecturer at RMS Annual Flow Cytometry Course
  • ​Regular contributor to ‘Flow Cytometry’ Channel on Bitesize Bio website.

Latest Publications

Aging yeast gain a competitive advantage on non-optimal carbon sources.
Frenk S, Pizza G, Walker RV, Houseley J

Animals, plants and fungi undergo an aging process with remarkable physiological and molecular similarities, suggesting that aging has long been a fact of life for eukaryotes and one to which our unicellular ancestors were subject. Key biochemical pathways that impact longevity evolved prior to multicellularity, and the interactions between these pathways and the aging process therefore emerged in ancient single-celled eukaryotes. Nevertheless, we do not fully understand how aging impacts the fitness of unicellular organisms, and whether such cells gain a benefit from modulating rather than simply suppressing the aging process. We hypothesized that age-related loss of fitness in single-celled eukaryotes may be counterbalanced, partly or wholly, by a transition from a specialist to a generalist life-history strategy that enhances adaptability to other environments. We tested this hypothesis in budding yeast using competition assays and found that while young cells are more successful in glucose, highly aged cells outcompete young cells on other carbon sources such as galactose. This occurs because aged yeast divide faster than young cells in galactose, reversing the normal association between age and fitness. The impact of aging on single-celled organisms is therefore complex and may be regulated in ways that anticipate changing nutrient availability. We propose that pathways connecting nutrient availability with aging arose in unicellular eukaryotes to capitalize on age-linked diversity in growth strategy and that individual cells in higher eukaryotes may similarly diversify during aging to the detriment of the organism as a whole.

+ View Abstract

Aging cell, , 1474-9726, , 2017

PMID: 28247585

Tracking the embryonic stem cell transition from ground state pluripotency.
Kalkan T, Olova N, Roode M, Mulas C, Lee HJ, Nett I, Marks H, Walker R, Stunnenberg HG, Lilley KS, Nichols J, Reik W, Bertone P, Smith A

Mouse embryonic stem (ES) cells are locked into self-renewal by shielding from inductive cues. Release from this ground state in minimal conditions offers a system for delineating developmental progression from naive pluripotency. Here we examined the initial transition process. The ES cell population behaves asynchronously. We therefore exploited a short-half-life Rex1::GFP reporter to isolate cells either side of exit from naive status. Extinction of ES cell identity in single cells is acute. It occurs only after near-complete elimination of naïve pluripotency factors, but precedes appearance of lineage specification markers. Cells newly departed from the ES cell state display features of early post-implantation epiblast and are distinct from primed epiblast. They also exhibit a genome-wide increase in DNA methylation, intermediate between early and late epiblast. These findings are consistent with the proposition that naive cells transition to a distinct formative phase of pluripotency preparatory to lineage priming.

+ View Abstract

Development (Cambridge, England), , 1477-9129, , 2017

PMID: 28174249

International Society for Advancement of Cytometry (ISAC) flow cytometry shared resource laboratory (SRL) best practices.
Barsky LW, Black M, Cochran M, Daniel BJ, Davies D, DeLay M, Gardner R, Gregory M, Kunkel D, Lannigan J, Marvin J, Salomon R, Torres C, Walker R

The purpose of this document is to define minimal standards for a flow cytometry shared resource laboratory (SRL) and provide guidance for best practices in several important areas. This effort is driven by the desire of International Society for the Advancement of Cytometry (ISAC) members in SRLs to define and maintain standards of excellence in flow cytometry, and act as a repository for key elements of this information (e.g. example SOPs/training material, etc.). These best practices are not intended to define specifically how to implement these recommendations, but rather to establish minimal goals for an SRL to address in order to achieve excellence. It is hoped that once these best practices are established and implemented they will serve as a template from which similar practices can be defined for other types of SRLs. Identification of the need for best practices first occurred through discussions at the CYTO 2013 SRL Forum, with the most important areas for which best practices should be defined identified through several surveys and SRL track workshops as part of CYTO 2014. © 2016 International Society for Advancement of Cytometry.

+ View Abstract

Cytometry. Part A : the journal of the International Society for Analytical Cytology, 89, 1552-4930, 1017-1030, 2016

PMID: 27813253

Facility Members

Latest Publications

Aging yeast gain a competitive advantage on non-optimal carbon sources.

Frenk S, Pizza G, Walker RV

Aging cell
1474-9726: (2017)

PMID: 28247585

Tracking the embryonic stem cell transition from ground state pluripotency.

Kalkan T, Olova N, Roode M

Development (Cambridge, England)
1477-9129: (2017)

PMID: 28174249

International Society for Advancement of Cytometry (ISAC) flow cytometry shared resource laboratory (SRL) best practices.

Barsky LW, Black M, Cochran M

Cytometry. Part A : the journal of the International Society for Analytical Cytology
89 1552-4930:1017-1030 (2016)

PMID: 27813253

The spindle assembly checkpoint works like a rheostat rather than a toggle switch.

Collin P,Nashchekina O,Walker R,Pines J

Nature cell biology
15 1476-4679:1378-85 (2013)

PMID: 24096242

Germline potential of parthenogenetic haploid mouse embryonic stem cells.

Leeb M,Walker R,Mansfield B,Nichols J,Smith A,Wutz A

Development (Cambridge, England)
139 1477-9129:3301-5 (2012)

PMID: 22912412

A high-throughput, flow cytometry-based method to quantify DNA-end resection in mammalian cells.

Forment JV,Walker RV,Jackson SP

Cytometry. Part A : the journal of the International Society for Analytical Cytology
81 1552-4930:922-8 (2012)

PMID: 22893507

A system for imaging the regulatory noncoding Xist RNA in living mouse embryonic stem cells.

Ng K,Daigle N,Bancaud A,Ohhata T,Humphreys P,Walker R,Ellenberg J,Wutz A

Molecular biology of the cell
22 1939-4586:2634-45 (2011)

PMID: 21613549

Oct4 and LIF/Stat3 additively induce Krüppel factors to sustain embryonic stem cell self-renewal.

Hall J,Guo G,Wray J,Eyres I,Nichols J,Grotewold L,Morfopoulou S,Humphreys P,Mansfield W,Walker R,Tomlinson S,Smith A

Cell stem cell
5 1875-9777:597-609 (2009)

PMID: 19951688

Intervertebral disc cell-mediated mesenchymal stem cell differentiation.

Richardson SM,Walker RV,Parker S,Rhodes NP,Hunt JA,Freemont AJ,Hoyland JA

Stem cells (Dayton, Ohio)
24 1066-5099:707-16 (2006)

PMID: 16223853