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Role of transposable elements in regulating gene expression in developing Pleurodeles waltl embryos

Dimitrijević, Milica (2025) MOBN03 20242
Degree Projects in Molecular Biology
Popular Abstract
How salamanders develop and regenerate with help from jumping genes

Salamanders are famous for something most animals cannot do – they can regenerate lost body parts like limbs and tail, and even parts of their internal organs. They can reactivate genes used during early development and create cells that can proliferate and compensate for the loss. For decades, scientists have studied these animals in hopes of uncovering secrets that might help human medicine. We fear the path to applying these findings to humans might not be straightforward. What we lack is huge genomes filled with transposable elements (TEs) that salamanders have. These pieces of DNA can move around the genome, earning them the nickname “jumping genes”. Mobility of... (More)
How salamanders develop and regenerate with help from jumping genes

Salamanders are famous for something most animals cannot do – they can regenerate lost body parts like limbs and tail, and even parts of their internal organs. They can reactivate genes used during early development and create cells that can proliferate and compensate for the loss. For decades, scientists have studied these animals in hopes of uncovering secrets that might help human medicine. We fear the path to applying these findings to humans might not be straightforward. What we lack is huge genomes filled with transposable elements (TEs) that salamanders have. These pieces of DNA can move around the genome, earning them the nickname “jumping genes”. Mobility of transposons can cause problems for their host, which is why they are tightly controlled to prevent harmful mutations. This is achieved through chemical modifications like DNA methylation or histone marks – tags on DNA-packaging proteins. But in some cases, TEs can be repurposed by the host genome to act as gene switches that help control when and where genes are turned on.

In our study, we investigated whether salamanders can use TEs as part of their development and regeneration program. We analyzed the chromatin landscape – how DNA is packed and marked – in regenerating axolotl limbs and in developing newt embryos. We reveal active and inactive regulatory regions, showing that many active regions (marked by H3K27ac or H3K4me3 histone marks), overlap with TEs. This suggests that salamanders may have repurposed TEs to act as switches for regulation of gene expression. Meanwhile, repressive marks like H3K9me3 keep other TEs silent, showing a careful balance between control and innovation. These findings support a growing view: TEs aren’t just “junk DNA”, but a powerful evolutionary toolkit. In salamanders, this seems to have been taken to an extreme: they may have harnessed the vast number of TEs in their genome to help coordinate the complex gene regulation needed for regeneration. To prove this, we need to test if these transposon-derived enhancers and promoters are truly essential for regeneration. Using tools like CRISPR interference (CRISPRi), we can try turning these switches off and see how it affects gene expression. This would be a major step toward proving that TEs are not just passengers in the genome, but drivers of development and regeneration.

Master’s Project in Molecular Biology: Molecular Genetics and Biotechnology
60 credits, MOBN03, Department of Biology, Lund University
Supervisor: Dr. Christopher Douse, Laboratory of Epigenetics and Chromatin Dynamics, Lund University
Co-supervisor: Dr. Nicholas Leigh, Regenerative Immunology Laboratory, Lund University (Less)
Please use this url to cite or link to this publication:
author
Dimitrijević, Milica
supervisor
organization
course
MOBN03 20242
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
9214485
date added to LUP
2025-10-24 11:47:35
date last changed
2025-10-24 11:47:35
@misc{9214485,
  author       = {{Dimitrijević, Milica}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Role of transposable elements in regulating gene expression in developing Pleurodeles waltl embryos}},
  year         = {{2025}},
}