MICROSCOPY UNIT

Head:

Publications

RNDr. Jan Malínský, Ph.D.
email: malinsky@biomed.cas.cz
tel: +420241062597

Ph.D. Students:

Vendula Strádalová
Mgr. Michaela Blažíková

Technical Assistants:

Jitka Eisensteinová
Lenka Hlavínová

Formation, distribution and dynamics of cellular structures not bound by membrane

Wide range of biomolecules is concentrated in specialized compartments within a cell, missing a well-defined boundary and thus communicating with the surroundings directly by diffusion, as highly dynamic, steady state organelles engaged in specific functions. Many of these compartments as nucleolus or Cajal body in the cell nucleus are well manifested under the microscope and known for a long time. Others have been described only recently and not widely accepted yet - for instance lipid raft-based compartments in membranes. Morphological changes or disintegration of these cellular structures go often along with pathologic phenotypes. The knowledge about composition, formation and maintenance of these structures is limited. We concentrate on

• Sites of DNA replication, their spatiotemporal distribution and dynamics
• Nucleolar formation, structure and its alterations
• snRNP assembly localization 
• Stability and maintenance of lateral domains within plasma membrane
• Functional relevance of lateral heterogeneity of plasma membrane composition in yeast, relation to structures in higher eukaryots

Here, a great deal is open for up-to-date microscopy techniques, capable not only to localize exactly the cellular components, but detect their movement and potential interactions at the molecular level as well.

Fig. 1: Evaluation of changes in replication foci distribution.

zoom figure

Sites of DNA replication were double-labeled using two different deoxynucleotide derivatives in HeLa cell nuclei (left). Different chases of 0 (upper) and 4 hours (lower) between the pulses were applied. The gradual changes in the replication foci distribution were monitored by cross-correlation function (middle) and 2D fluorescence intensity histograms (right) from early to mid S phase (Masata et al., 2005).

Fig. 2: Dynamics of protein domains in the plasma membrane of S.cerevisiae.

zoom figure

Tangential optical section of a cell expressing plasma membrane proton ATP-ase Pma1GFP was scanned repeatedly during cell growth. The lateral diffusion of the protein is confined to the network-like area of MC P. Note the growing bud in the left part of the image and the enormously stable pattern of non-fluorescing MC C patches devoid of Pma1p. Numbers indicate the minutes elapsing since the start of the examination. Bar: 5 µm (Malinska et al., 2003).

Fig. 3: Fur4p, Sur7p and Can1p co-localize in membrane compartment C.

zoom figure

Simultaneous localizations of Can1GFP/Sur7mRFP (left) and Fur4GFP/Sur7mRFP (right) were performed. The fluorescence-intensity profiles along the cell surface (outside the dashed arrows) were plotted. Note the co-localization of fluorescence intensity maxima. The curves were smoothed using a mean filter to reduce the noise (Malinska et al., 2004).

List of current grants:

Name of the grant	Grant agency	Number of the grant	Principal investigator	Duration of the grant
Self-organization principles of non-membrane-bound organels in eukaryotic cells	GAČR	204/07/0133	-	2007-11

1994 | 1996 | 1997 | 1998 | 1999 | 2000 | 2001 | 2002 | 2003 | 2004 | 2005 | 2006 | 2007 | 2008