The human body consists of hundreds, perhaps thousands of different types of cells, each with different morphologies and functions, despite having the same genome.

John van Noort

Efficient gene-targeting during meiosis

Biosynthetic gene clusters (BGCs) for natural products are widespread in microbial genomes, and they are rapidly exchanged. This research assesses the factors that control the spread of BGCs and resistance genes in nature. This includes risk assessment for the spread of engineered DNA in nature.

The objective of this study was to investigate the expression and function of GRHL2 in different breast cancer subtypes.

Promotor: Prof.dr. G.P. van Wezel

Promotores: T.H.W. Bäck, A. Plaat, Co-promotor: F.J. Verbeek

In this thesis, we used genetically engineered mouse models to identify genes and pathways that are involved in ILC formation and in the development of resistance to FGFR-targeted therapy.

This project aims to assess the risk of spread of antimicrobial resistance genes in the environment derived from currently used synthetic biology approaches in the field of drug discovery.

Streptomyces bacteria are a valuable source of natural products, many of which are used in the clinic or in biotechnology.

Nucleoid associated proteins maintain the architecture of the bacterial chromosome and regulate gene expression, hinting that their role as transcription factors may involve local three-dimensional chromosome re-modelling.

This thesis describes the functional analysis of the Arabidopsis AHL15 gene.

The bacterial cell wall is a nearly universal structure that offers protection and gives the cell its shape. However, environmental stressors, such as cell wall-targeting antibiotics and hyperosmotic conditions, can induce bacteria to shift to a wall-deficient state. It is unknown whether the lack of…

Which genes are involved in woodiness and associated traits such as drought tolerance, flowering time, stem elongation, life span, and plant herbivory, and how do these gene regulatory pathways overlap?

Promotor: P.J.J. Hooykaas, Co-Promotores: P.B.F. Ouwerkerk, M. Wang

DNA carries various forms of information. Out of these forms of information the most well-known is classical genetic information.

In this Ph.D. thesis, we characterized two novel upstream regulators of JUB1, HB40, and HB22, in Arabidopsis thaliana. In Chapter 2, we described functions of HB40 in modulating growth and development via the regulation of JUB1 and GA inactivation genes GA2OXs.

Plant architecture has distinct forms in different plant species, but also within a species the finalarchitecture of a plant is determined by its gradual development and changes therein induced by environmental conditions during the plant’s life cycle.

Drug induced organ toxicity is the main problem of the drug development and drug usage in the clinic. The liver and kidneys are the most sensitive organs towards drug induced toxicity.

My PhD project studies how the temporally sequential Hox gene expression is regulated during head-tail patterning of the frog embryo.

Harvesting rice from the same field, without planting new rice plants? A discovery may bring this scenario closer. Leiden scientists have discovered a gene that allows annual plants to grow after flowering, instead of dying. Publication on 13 April in Nature Plants.

The experiments described in this thesis employ local lentiviral knockdowns in brain areas of female zebra finches followed by behavioural assays consisting of preference and Go/Nogo tasks.

We exploit secondary metabolites of plant to develop pharmaceutical compounds and we genetically modify plant genomes to improve crops.

Just like us, plants also produce growth hormones, and they also go through an ageing process. The study of the genes and mechanisms behind these processes is useful not only for crop breeding and agriculture, but also for medical research. That is the view held by Professor of Plant Developmental Genetics…

PhD student Esmee Koedoot studied the underlying processes responsible for metastases in a dangerous type of breast cancer. She hopes to find new possibilities to fight the disease. In December 2019 she obtained her doctorate cum laude.

Climate change is a challenge for both current and future generations. New biological resources have to be developed in order to meet the demand for energy as well as the demand for food.

Researchers at Leiden University have mapped genes that cause breast cancer cells to migrate. The Leiden toxicologists Professor Bob van de Water, Dr Wies van Roosmalen, Dr Sylvia E. Le Dévédec and colleagues studied 1500 individual genes. They found eight, including the SRPK1 gene, that regulate the…

Salicylic acid (SA) is a plant hormone, which is involved in the defense responses to pathogens and to abiotic stress, and in the regulation of plant growth and development.

Plant-microbe interaction resulted in different physio/chemical responses by host plant and interacting rhizobacteria.

Leiden biologists have shown that a gene present in plants, animals and yeasts does play an important role in plants, although for years the gene was considered unimportant. It turns out the gene plays a crucial role in the development of vascular tissue in plants. Publication in Nature Plants on 11…

‘It was a discovery we did not expect,’ says Remko Offringa, professor of Plant developmental genetics. Today he publishes a new trait of a versatile gene in Current Biology: it makes the difference in plants between herbaceous and woody stem growth. A useful feature to prevent dehydration.

The way genes are folded determines their activity in our body. Leiden biophysicists are now the first to unravel this structure molecule-by-molecule. Publication on December 1st in Nature’s Scientific Reports.

A publication in Nature Plants by a team of Leiden biologists has received national and international media attention. The researchers can have annuals flower multiple times thanks to a particular gene they discovered.

Master's student Thalia Luden receives an NWO grant for her research proposal about a gene that brings flowering plants back into a growth phase. Companies in floriculture and vegetable seed breeding also contribute to the research.

In a publication in Science, Noam Zelcer from the Division of Biopharmaceutics describes a previously unrecognized pathway to regulate LDL-cholesterol levels. He is also able to modulate this pathway. This opens the possibility for complementing and improving the efficacy of statins: A class of drugs…

Researchers from the Leiden University Medical Center (LUMC) have successfully used stem cell gene therapy to treat a baby with the severe congenital immune disorder SCID. An important milestone: it is the first time stem cell gene therapy of Dutch origin has been administered to a patient, and also…

How do plant defense genes get activated?

To gain more insight into the evolutionary development of orchid flowers and fruits, the orchid species Erycina pusilla was studied. The evolutionary origin of the median petaloid sepal, the callus on the labellum, and the stelidia was studied.

The molecular mechanisms that instigate a healthy cell to become malignant are fueled by (epi)genetic alterations in so-called driver genes.

Pectin is a plant cell wall polysaccharide made of mainly D-galacturonic acid (GA) subunits. The potency of the filamentous fungus Aspergillus niger to naturally secrete high amounts of pectinases to degrade pectin has been utilized for the industrial production of pectinases.

Promotores: Prof.dr. M.K. Richardson, Prof.dr. H.P. Spaink

Soil is a home for an unbelievable diversity and abundance of microbial life that is essential for supporting life on our planet.

Increasing the efficiency of gene targeting (GT) as a genome editing tool in plants has been an important goal in plant biotechnology.

How did toxin genes evolve from harmless physiological genes?

In recent decades, climate change has led to more frequent and severe drought events, causing serious consequences such as increased forest mortality and significant crop yield losses. Understanding how drought affects plants, especially economically important herbaceous species, is crucial for predicting…

What are the genes and molecular mechanisms involved in bacteria-mediated plant drought tolerance?

Promotor: G.P. van Wezel, Co-promotor: Y.H. Choi

Some people are predisposed to develop cancer. Mutations in genetic material that increase a person’s chances of developing cancer can already be present at birth. Researchers are closely examining these mutations to learn more about how cancer begins to develop.

Can epigenetic changes explain associations between early life stress and health outcomes?

Promotor: Prof.dr. H.P. Spaink, Co-promotor: Prof.dr. A.H. Meijer