Christian Kroun Damgaard

Christian Kroun Damgaard

Associate professor

Research area: Investigating the roles of non-coding RNA and RNA binding proteins in regulated RNA decay and translation

Damgaard Lab

 

The broad aim of my research group is to decipher the molecular mechanisms underlying regulated mRNA decay and translation during cellular stress, processes that are often deregulated in disease. 

Cellular stress re-programs gene-expression both at the transcriptional and post-transcriptional levels. Transcriptional events have traditionally received most attention in the past, but it has become increasingly clear that post-transcriptional regulation of gene-expression, such as modulation of mRNA decay rates and translation, plays an equally important role for a proper regulation of the eukaryotic transcriptome. We use primary human cells and cell-lines as model systems to directly study how mRNA decay and translation is regulated by interaction with a variety of RNA-binding proteins and non-coding RNAs. We utilize cellular imaging, including fluorescent in situ hybridization (RNA-FISH), immunofluorescence and both global and local molecular biological and biochemical approaches to address three major focus areas of our research:

1.  Post-transcriptional gene regulation during stress

We have recently revealed that the RNA-binding proteins, LARP1, TIA-1 and TIAR, work as important translational repressors of a certain class of mRNAs containing a 5'Terminal OligoPyrimidine tract (5'TOP) during cellular stress. Our current research efforts focus on further defining the mechanistic details by which these proteins act to repress translation and also impact mRNA decay during stress. These studies include various 5’TOP reporter assays as well as global RNA-sequencing (RNA-seq) and mass spectrometry (MS) assays, which aim at identifying novel RNA targets and mechanisms of translation/mRNA decay regulation.

2.  Regulation of neuronal differentiation by circular RNAs and RNA binding proteins

A vast number of important non-coding RNAs (ncRNAs) are expressed from the mammalian genome. These ncRNAs include recently identified circular RNAs (circRNAs) that arise from seemingly inefficient back-splicing events facilitated by the canonical splicing machinery. While roles for circRNAs has been described in both transcriptional and post transcriptional cellular events, little is still known about the their general mode of action. Many circRNAs become highly upregulated during neuronal differentiation and we are currently investigating whether this differential expression can directly modulate neuronal development. We have developed tools for manipulating circRNAs by knockdown/overexpression and imaging, which we combine with cell biological phenotypes and assessment of transcriptomes (RNA-seq) and proteomes (MS). 

3. Circular RNAs in disease

We have recently identified many circRNAs that are differentially expressed in disease, including various cancers and myotonic dystrophy. Current projects serve to study whether these changes in circRNA expression are merely a result of a general massive transcriptomal alteration in these diseases or whether there could be direct drivers of diseases states among the circRNAs. We wish to further elucidate the molecular mechanisms of action by a number of promising candidate circRNAs.


Figure legend:

RNA-FISH experiment showing a 5'TOP-mRNA reporter accumulating in stress granules in HeLa cells.

Click figure for enlargement.