Hausmann, M., Liebe, B., Perner, B., Jerratsch, M., Greulich, K. O. and Scherthan, H.
Imaging of human meiotic chromosomes by scanning near-field optical microscopy (SNOM). Micron 34: 441-447 (2003).

Centromeres and telomeres are key structures of mitotic and meiotic chromosomes. Especially telomeres develop particular structural properties at meiosis. Here, we investigated the feasibility of scanning near-field optical microscopy (SNOM) for light-microscopic imaging of meiotic telomeres in the sub-hundred nanometer resolution regime. SNOM was applied to visualize the synaptonemal complex (SC) and telomere proteins (TRF1, TRF2) after differential immuno-fluorescent labelling. We tested and compared two different preparation protocols for their applicability in a SNOM setting using micro-fabricated silicon nitride aperture tips. Protocol I consisted of differential labelling of meiotic chromosome cores (SC) by SCP3 immuno-fluorescence and telomeres by TRF1 or TRF2 immuno-fluorescence, while protocol II combined absorption labelling with alkaline phosphatase substrates of cores with fluorescent labelling of telomeres. The results obtained indicate that protocol I reveals a better visualization of structural (topographic) details than protocol II. By means of SNOM, meiotic chromosome cores could be visualized at a resolution overtopping that of far-field light microscopy.