Small RNAs and their role in growth, development and infection
The main focus of our research is to understand how different biological processes are controlled by non-coding (nc)RNAs, with emphasis on gene regulation by small RNAs such as micro(mi)RNAs. For our studies we mainly use the genetically tractable social amoeba Dictyostelium discoideum, a unicellular organism that upon starvation enters a multicellular developmental program where cells differentiate and communicate.
NcRNAs are RNA molecules that are not translated. Instead, they have intrinsic functions, often executed by binding to complementary (m)RNA sequences to which they guide effector proteins. This can induce cleavage, DNA/RNA modifications, translational inhibition and much more. One class of ncRNAs is miRNAs, only ~21 nt long. These small RNAs bind to mRNAs and induce cleavage and/or translational inhibition and thereby down regulate gene expression. In humans miRNAs have been estimated to directly regulate about 60% of the genes, underscoring their importance.
One of our research aims is to better understand the biogenesis and function of miRNAs. Although miRNAs previously was believed to be unique to plants and animals, we and others have now shown that they are also present in some unicellular organisms, such as Dictyostelium. In order to study the function of miRNAs, we construct knock out strains of miRNA associated genes and investigate the effects on growth and development. We also use high throughput sequencing of small RNAs and mRNAs, of strains with different genetic backgrounds to nail down miRNA regulated target genes. In addition, we are interested in small RNAs involvement during infection by pathogenic bacteria, using Dictyostelium as a host model. Another project is to further reveal the function of an abundant class of ~50-90 nt long RNAs that previously discovered and that seem to play a role during early development in Dictyostelium.