The Regulation of Chromosome Axis formation in Plant Meiosis
Lead Research Organisation:
University of Birmingham
Department Name: Sch of Biosciences
Abstract
In all sexually reproducing eukaryotes, meiotic recombination is essential for the maintenance of the ploidy level of the species, and the introduction of genetic variation. Both require genetic crossovers (COs) formed during meiosis.
The first step in CO formation is the production of double strand breaks (DSBs) in DNA. In many species, the number of DSBs produced far outweighs the number of COs that eventually resolve; in Arabidopsis thaliana, approximately 5% of DSBs will become COs. Several levels of control on CO frequency and distribution have previously been elucidated. In many cereal species such as Wheat, these stringent controls on recombination result in up to 50% of the genetic information being inaccessible to plant breeders.
It is still not fully understood how the decision to make a CO is made, but it is known that the interaction between the recombination machinery, the chromosome axis, and the global remodelling of chromosomes during meiosis is crucial. Investigating the role of the chromosome axis in meiosis is therefore essential if we are to learn how we might manipulate meiotic recombination, and allow crop breeders to more rapidly develop new, improved cultivars. Through a combination of innovative molecular and cytogenetic techniques, this PhD project aims to further our understanding of the role of the chromosome axes in meiosis, and how individual proteins are regulated. This will include investigation of the protein-protein interactions and post-transcriptional modifications that may influence the regulation and role of several core axis proteins, as well as the use of super-resolution microscopy to visualise the axis in greater detail.
The first step in CO formation is the production of double strand breaks (DSBs) in DNA. In many species, the number of DSBs produced far outweighs the number of COs that eventually resolve; in Arabidopsis thaliana, approximately 5% of DSBs will become COs. Several levels of control on CO frequency and distribution have previously been elucidated. In many cereal species such as Wheat, these stringent controls on recombination result in up to 50% of the genetic information being inaccessible to plant breeders.
It is still not fully understood how the decision to make a CO is made, but it is known that the interaction between the recombination machinery, the chromosome axis, and the global remodelling of chromosomes during meiosis is crucial. Investigating the role of the chromosome axis in meiosis is therefore essential if we are to learn how we might manipulate meiotic recombination, and allow crop breeders to more rapidly develop new, improved cultivars. Through a combination of innovative molecular and cytogenetic techniques, this PhD project aims to further our understanding of the role of the chromosome axes in meiosis, and how individual proteins are regulated. This will include investigation of the protein-protein interactions and post-transcriptional modifications that may influence the regulation and role of several core axis proteins, as well as the use of super-resolution microscopy to visualise the axis in greater detail.
Publications
Kuo P
(2022)
Super-resolution Chromatin Visualization Using a Combined Method of Fluorescence In Situ Hybridization and Structured Illumination Microscopy in Solanum lycopersicum.
in Methods in molecular biology (Clifton, N.J.)
Chambon A
(2018)
Identification of ASYNAPTIC4, a Component of the Meiotic Chromosome Axis.
in Plant physiology
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| BB/M01116X/1 | 01/10/2015 | 31/03/2024 | |||
| 1644151 | Studentship | BB/M01116X/1 | 05/10/2015 | 30/09/2019 | Alice Darbyshire |
| Description | ASY4 is a crucial component of the meiotic chromosome axis in the plant model organism Arabidopsis thaliana. We published one version of a mutant with Mathilde Grelon's group at the INRA Versailles that I prove is a hypomorphic mutant, that is, it is not a true null mutant of ASY4. Thus, using CRISPR/Cas9, I have developed a true ASY4-null mutant. I present a different phenotype to that observed with Grelon et al., the results of which I anticipate in these last few months of my PhD. |
| Exploitation Route | The antibodies I produced and verified are now a stock that can be shared within the meiosis community worldwide. My results show that ASY4/ASY3 are executing similar roles to SYCP1/SYCP2 in mouse, which will for other groups suggest further avenues of research. If my mutant appears to have altered crossover (CO) localisation, then this would be useful for plant breeders, as the entire point of my research is to better understand the processes that govern where COs are deposited; this is so breeders can access the areas of the genome in crops that may contain useful variants of genes, or indeed, to break up the linkage between unfavourable alleles and favourable ones. |
| Sectors | Agriculture, Food and Drink,Other |
| Description | ASY4 |
| Organisation | French National Institute of Agricultural Research |
| Department | INRA Versailles |
| Country | France |
| Sector | Academic/University |
| PI Contribution | Cytology: analysis of mutant lines, and complemented mutant lines. Our group was solely responsible for production of an eYFP tagged plant line, and all the associated analysis. We also contributed to the writing of the associated paper. We initially identified the protein independently. Development of the asy4-4 CRISPR/Cas9 knock-out mutant line. All analysis of said line. |
| Collaborator Contribution | INRA: Initial analysis of mutant plant lines, independently discovered the protein. Obtained the mutant lines. Wrote the majority of the paper. Gave us the original seeds. Cytological analysis, and RT-PCR. IPK: Invited by Dr Stefan Heckmann to learn techniques, free of charge, in his laboratory. JIC: Prof Kirsten Bomblies allowed me to use their SIM Microscope free of charge for three days to image cells from this project. |
| Impact | INRA: Identification of ASYNAPTIC4, a Component of the Meiotic Chromosome Axis. Published in Plant Physiology 2018. JIC: Publication currently being written. |
| Start Year | 2015 |
| Description | ASY4 |
| Organisation | IPK Gatersleben |
| Country | Germany |
| Sector | Private |
| PI Contribution | Cytology: analysis of mutant lines, and complemented mutant lines. Our group was solely responsible for production of an eYFP tagged plant line, and all the associated analysis. We also contributed to the writing of the associated paper. We initially identified the protein independently. Development of the asy4-4 CRISPR/Cas9 knock-out mutant line. All analysis of said line. |
| Collaborator Contribution | INRA: Initial analysis of mutant plant lines, independently discovered the protein. Obtained the mutant lines. Wrote the majority of the paper. Gave us the original seeds. Cytological analysis, and RT-PCR. IPK: Invited by Dr Stefan Heckmann to learn techniques, free of charge, in his laboratory. JIC: Prof Kirsten Bomblies allowed me to use their SIM Microscope free of charge for three days to image cells from this project. |
| Impact | INRA: Identification of ASYNAPTIC4, a Component of the Meiotic Chromosome Axis. Published in Plant Physiology 2018. JIC: Publication currently being written. |
| Start Year | 2015 |
| Description | ASY4 |
| Organisation | John Innes Centre |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | Cytology: analysis of mutant lines, and complemented mutant lines. Our group was solely responsible for production of an eYFP tagged plant line, and all the associated analysis. We also contributed to the writing of the associated paper. We initially identified the protein independently. Development of the asy4-4 CRISPR/Cas9 knock-out mutant line. All analysis of said line. |
| Collaborator Contribution | INRA: Initial analysis of mutant plant lines, independently discovered the protein. Obtained the mutant lines. Wrote the majority of the paper. Gave us the original seeds. Cytological analysis, and RT-PCR. IPK: Invited by Dr Stefan Heckmann to learn techniques, free of charge, in his laboratory. JIC: Prof Kirsten Bomblies allowed me to use their SIM Microscope free of charge for three days to image cells from this project. |
| Impact | INRA: Identification of ASYNAPTIC4, a Component of the Meiotic Chromosome Axis. Published in Plant Physiology 2018. JIC: Publication currently being written. |
| Start Year | 2015 |
| Description | A-Level Revision Podcasts |
| Form Of Engagement Activity | A broadcast e.g. TV/radio/film/podcast (other than news/press) |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Schools |
| Results and Impact | Podcasts developed and made available to people worldwide who wish to know more about certain topics in biology, but was especially targeted at A-Level students wishing to know more about research. |
| Year(s) Of Engagement Activity | 2016 |
| URL | https://www.birmingham.ac.uk/undergraduate/preparing-for-university/stem/STEM-resources.aspx?utm_sou... |
| Description | MEICOM Meet The Scientist |
| 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 | Along with the students from the MEICOM network, we executed a 'Meet The Scientist' event at the Think Tank Museum, Birmingham, during the February half term. Thousands of people were expected to visit on this day. |
| Year(s) Of Engagement Activity | 2019 |
| Description | University of The Third Age |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Public/other audiences |
| Results and Impact | The Science Branch of The University of The Third Age arrange a monthly talk. After approaching them, they agreed to let me speak to them about the uses of gene editing technologies and meiosis research to contribute toward ensuring food security in the future. The full cohort attended, which is 10 people. My aim was to both alert them to the issues surrounding food security, and to find out how much they knew about GE technologies, with focus on CRISPR/Cas9. The idea was to give an unbiased discussion that was purely informational, and determine if there had been a shift in opinion without any biased input. They were surveyed before hand. Only two said they would eat a GM crop. After the talk, 9 said they would. They also fed back that they had not realised the importance of meiosis research, and how GE/GM open up a lot more possibilities for plant breeders. They said they would ensure they spoke to their friends about GM, as some felt strongly that the media had been painting a negative picture of the technology. No media engagement. No external resources were required. |
| Year(s) Of Engagement Activity | 2016 |
| Description | UoB School |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Schools |
| Results and Impact | I approached the University of Birmingham School to give a talk to A-Level students on my research. These students had signed up to a lunchtime workshop where they could hear from PhD students and other researchers about their experiences, including how to get into university in the first place. Around 30 people attended. I spoke about my academic progression, and gave advice on their future choices, funding etc. I then went on to discuss meiosis in-depth: they had not yet covered in their lessons that the chromosomes have an axis, nor anything to do with how COs are not uniformly distributed throughout the genome, and the problems that arise because of it. The teachers said it would supplement the pupils' understanding of meiosis, and also, could potentially influence their teaching of the topic. |
| Year(s) Of Engagement Activity | 2015 |