Atypical DNA replication in the absence of origins in archaeon Haloferax volcanii

Lead Research Organisation: University of Nottingham
Department Name: School of Life Sciences


DNA replication is widely accepted to initiate at specific areas within the genome, known as 'origins of replication'. Whilst origins were previously thought to be essential for survival, deletion of all chromosomal origins of replication in archaeon Haloferax volcanii has no ill effect, with originless cells growing 7.5% faster than the wild type strain (Hawkins et al., 2013, Nature, doi:10.1038/nature12650).

Initiation of replication is generally well understood: origin recognition proteins remodel DNA at the origin to a more open structure, allowing loading of replication components, which will form a functional 'replisome' that will replicate the DNA. Little is known about how DNA is replicated without origins; origins and origin recognition proteins are non-essential in H. volcanii, and thus an alternate mode of replication initiation must be occurring. This project aims to assess how the molecular mechanisms of replication are altered in cells lacking origins of replication. The components required for replication will be analysed and differences between origin-dependent and origin-independent replication will be assessed.


10 25 50

Studentship Projects

Project Reference Relationship Related To Start End Student Name
BB/M008770/1 01/10/2015 31/10/2024
1944984 Studentship BB/M008770/1 01/10/2017 30/09/2021
Title Haloferax volcanii strains for CRISPRi experiments 
Description Strains are now available lacking Cas3 and Cas6 proteins, meaning CRISPR interference (CRISPRi) techniques can be used. These are available both in a wild-type background and in a background where origins of replication have been deleted. 
Type Of Material Cell line 
Year Produced 2019 
Provided To Others? No  
Impact Creation of these strains allows for interference with the transcription of any gene of choice within Haloferax volcanii. Therefore, should the importance of a gene need to be studied where other techniques may not work, CRISPRi can target the gene promoter causing a knockdown in expression level. 
Description Microbiology Society blog article - Engaging with the research around me 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact This blog post covered attendance at the University of Nottingham Postgraduate Research Symposium 2019; this event was sponsored by the Microbiology Society. Writing this piece allowed me to reflect on the vast range of research taking place at the University of Nottingham and engage with my peers and their work. It also started a working relationship between myself and a member of the Society staff that has since led to me writing a further article for the Society webpage.
Year(s) Of Engagement Activity 2019
Description Science in the Park display 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact The Science in the Park event was a local event showcasing local science to the general public. Approximately 300 people attended and I was involved as part of a stand on evolution, along with two others. The meeting was well organised meaning there was a consistent stream of people around to interact with. Having had multiple meetings prior to the day, our group showed up with a clear idea on what was expected from us and with the activities fully prepared and tested.

To start with I found it difficult to engage children who had no background knowledge of evolution, but with more practice I understood to engage the children you needed to ask a question they could understand; in this case 'Do you know why all birds don't have the same beak?'. By relating the problem to something they can easily understand it was easy to get them engaged as the young audience wanted to answer the questions correctly.
I feel our activity was simple but effective at explaining that different foods require different beaks, with the majority of children remaining engaged and understanding the takeaway method. Parents also complimented the simplicity of the activity to explain an otherwise difficult to explain topic.

The only downside to our activity was it targeted a younger audience, thus older children were not engaged. However, I think it was important to
get the message over to the younger children and the activity managed this successfully. I believe it would have required a separate stand to cover the more in-depth evolutionary knowledge, which would then have not appealed to the younger audience we targeted here.
Overall being involved in science outreach was an enjoyable experience.
Year(s) Of Engagement Activity 2018