Overview
My PhD focussed on understanding how the CRISPR-Cas immune system is updated to target newly encountered foreign genetic elements. In the Westra group in the ESI I have started to investigate the importance of the type I-F CRISPR-Cas system of Pseudomonas aeruginosa in protection against temperate phage and the fitness consequences of this immunity for the host and the phage parasite.
Qualifications
2016 PhD - Biochemistry, University of St Andrews
2011 BSc (Hons) - Biology with French (with integrated year abroad), University of St Andrews
Links
Publications
Key publications | Publications by category | Publications by year
Publications by category
Journal articles
Chevallereau A, Meaden S, van Houte S, Westra ER, Rollie C (2019). The effect of bacterial mutation rate on the evolution of CRISPR-Cas adaptive immunity.
Philos Trans R Soc Lond B Biol Sci,
374(1772).
Abstract:
The effect of bacterial mutation rate on the evolution of CRISPR-Cas adaptive immunity.
CRISPR-Cas immune systems are present in around half of bacterial genomes. Given the specificity and adaptability of this immune mechanism, it is perhaps surprising that they are not more widespread. Recent insights into the requirement for specific host factors for the function of some CRISPR-Cas subtypes, as well as the negative epistasis between CRISPR-Cas and other host genes, have shed light on potential reasons for the partial distribution of this immune strategy in bacteria. In this study, we examined how mutations in the bacterial mismatch repair system, which are frequently observed in natural and clinical isolates and cause elevated host mutation rates, influence the evolution of CRISPR-Cas-mediated immunity. We found that hosts with a high mutation rate very rarely evolved CRISPR-based immunity to phage compared to wild-type hosts. We explored the reason for this effect and found that the higher frequency at which surface mutants pre-exist in the mutator host background causes them to rapidly become the dominant phenotype under phage infection. These findings suggest that natural variation in bacterial mutation rates may, therefore, influence the distribution of CRISPR-Cas adaptive immune systems. This article is part of a discussion meeting issue 'The ecology and evolution of prokaryotic CRISPR-Cas adaptive immune systems'.
Abstract.
Author URL.
Full text.
Rollie C, Graham S, Rouillon C, White MF (2018). Prespacer processing and specific integration in a Type I-A CRISPR system.
NUCLEIC ACIDS RESEARCH,
46(3), 1007-1020.
Author URL.
Full text.
Peeters E, Boon M, Rollie C, Willaert R, Voet M, Prangishvili D, Lavigne R (2017). DNA-Interacting Characteristics of the Archaeal Rudiviral Protein SIRV2_Gp1.
Viruses,
9(7), 190-190.
Full text.
Rollie C, Schneider S, Brinkmann AS, Bolt EL, White MF (2015). Intrinsic sequence specificity of the Cas1 integrase directs new spacer acquisition.
eLife,
4Abstract:
Intrinsic sequence specificity of the Cas1 integrase directs new spacer acquisition
The adaptive prokaryotic immune system CRISPR-Cas provides RNA-mediated protection from invading genetic elements. The fundamental basis of the system is the ability to capture small pieces of foreign DNA for incorporation into the genome at the CRISPR locus, a process known as Adaptation, which is dependent on the Cas1 and Cas2 proteins. We demonstrate that Cas1 catalyses an efficient trans-esterification reaction on branched DNA substrates, which represents the reverse- or disintegration reaction. Cas1 from both Escherichia coli and Sulfolobus solfataricus display sequence specific activity, with a clear preference for the nucleotides flanking the integration site at the leader-repeat 1 boundary of the CRISPR locus. Cas2 is not required for this activity and does not influence the specificity. This suggests that the inherent sequence specificity of Cas1 is a major determinant of the adaptation process.
Abstract.
Full text.
Publications by year
2019
Chevallereau A, Meaden S, van Houte S, Westra ER, Rollie C (2019). The effect of bacterial mutation rate on the evolution of CRISPR-Cas adaptive immunity.
Philos Trans R Soc Lond B Biol Sci,
374(1772).
Abstract:
The effect of bacterial mutation rate on the evolution of CRISPR-Cas adaptive immunity.
CRISPR-Cas immune systems are present in around half of bacterial genomes. Given the specificity and adaptability of this immune mechanism, it is perhaps surprising that they are not more widespread. Recent insights into the requirement for specific host factors for the function of some CRISPR-Cas subtypes, as well as the negative epistasis between CRISPR-Cas and other host genes, have shed light on potential reasons for the partial distribution of this immune strategy in bacteria. In this study, we examined how mutations in the bacterial mismatch repair system, which are frequently observed in natural and clinical isolates and cause elevated host mutation rates, influence the evolution of CRISPR-Cas-mediated immunity. We found that hosts with a high mutation rate very rarely evolved CRISPR-based immunity to phage compared to wild-type hosts. We explored the reason for this effect and found that the higher frequency at which surface mutants pre-exist in the mutator host background causes them to rapidly become the dominant phenotype under phage infection. These findings suggest that natural variation in bacterial mutation rates may, therefore, influence the distribution of CRISPR-Cas adaptive immune systems. This article is part of a discussion meeting issue 'The ecology and evolution of prokaryotic CRISPR-Cas adaptive immune systems'.
Abstract.
Author URL.
Full text.
2018
Rollie C, Graham S, Rouillon C, White MF (2018). Prespacer processing and specific integration in a Type I-A CRISPR system.
NUCLEIC ACIDS RESEARCH,
46(3), 1007-1020.
Author URL.
Full text.
2017
Peeters E, Boon M, Rollie C, Willaert R, Voet M, Prangishvili D, Lavigne R (2017). DNA-Interacting Characteristics of the Archaeal Rudiviral Protein SIRV2_Gp1.
Viruses,
9(7), 190-190.
Full text.
2015
Rollie C, Schneider S, Brinkmann AS, Bolt EL, White MF (2015). Intrinsic sequence specificity of the Cas1 integrase directs new spacer acquisition.
eLife,
4Abstract:
Intrinsic sequence specificity of the Cas1 integrase directs new spacer acquisition
The adaptive prokaryotic immune system CRISPR-Cas provides RNA-mediated protection from invading genetic elements. The fundamental basis of the system is the ability to capture small pieces of foreign DNA for incorporation into the genome at the CRISPR locus, a process known as Adaptation, which is dependent on the Cas1 and Cas2 proteins. We demonstrate that Cas1 catalyses an efficient trans-esterification reaction on branched DNA substrates, which represents the reverse- or disintegration reaction. Cas1 from both Escherichia coli and Sulfolobus solfataricus display sequence specific activity, with a clear preference for the nucleotides flanking the integration site at the leader-repeat 1 boundary of the CRISPR locus. Cas2 is not required for this activity and does not influence the specificity. This suggests that the inherent sequence specificity of Cas1 is a major determinant of the adaptation process.
Abstract.
Full text.
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