Research 

Dynamics of nuclear signaling

nuclearA-kinase anchoring proteins, or AKAPs, target the cAMP-dependent protein kinase (PKA) and other signaling molecules to specific subcellular loci for maximum enzyme efficacy. We are investigating the functional properties of AKAP149, involved in the regulation of nuclear envelope dynamics and possibly RNA metabolism. We also study the nuclear PP1 targeting subunit PNUTS, which we found is implicated in chromosome dynamics and in cell cycle control.

Figure: Intranuclear foci formed by the KH-Tudor domain of AKAP149, here fused to GFP (green). Red shows upstream binding factor (UBF) labeling.

Video - Laser scanning confocal analysis of HeLa cell nuclei showing PNUTS (green) and sc35 (red).

Nuclear reprogramming

The mechanisms underlying genomic plasticity are poorly understood. Alteration of cell fate involves a reprogramming of nuclear function. Using cellular extract-based approaches, we are exploring the transdifferentiation and dedifferentiation capacities of somatic cells.

Figure: Epithelial 293T cells reprogrammed into embryonic stem-like cells using extract from pluripotent cells.
 

Epigenetics of mesenchymal stem cells

The stromal compartment of mesenchymal tissues harbors multipotent stem or progenitor cells that display proliferative capacity in culture, and multilineage differentiation potential. A recent research axis in our lab is the characterization of the molecular processes that govern ‘stemness’ in freshly isolated and cultured stem cells purified from adipose tissue.

Figure: Adipocytes differentiated from adipose stem cells. Intracellular lipid droplets are stained with Oil Red-O.

 

Chromatin immunoprecipitation assays

Chromatin immunoprecipitation (ChIP) is a powerful technique to map the binding of post-transcriptionally modified histones, transcription factors or other proteins on DNA in the genome. We have developed fast ChIP assays suitable for very small cell numbers, which open doors to epigenetic analyses of cell and tissue samples up to now excluded from such investigations.