Small RNA pathways in Paramecium: epigenetic inheritance and the control of antigenic variation

One aspect of our research uses the unicellular ciliate Paramecium as an epigenetic model. Long time ago, in 1948, Sonneborn & LeSuer described several phenomena of the inheritance of characters not following Mendelian genetics. Instead, expression of individual characters follows the cytoplasmic lineage: individuals express different genes although being genetically identical.

One example for cytoplasmic inheritance are the serotype genes: Paramecium undergoes Antigenic Variation similar to pathogenic protists. For these genes we identified RNA components and small RNAs regulating Antigenic Variation at the chromatin level. Our research focuses on the detailed function and transport of these siRNAs aiming to answer the questions why, when and how they are transported to the developing Macronucleus during sexual recombination.