A glue for heterochromatin maintenance: stable SUV39H1 binding to heterochromatin is reinforced by the SET domain.

Trimethylation of histone H3 lysine 9 and the subsequent binding of heterochromatin protein 1 (HP1) mediate the formation and maintenance of pericentromeric heterochromatin. Trimethylation of H3K9 is governed by the histone methyltransferase SUV39H1. Recent studies of HP1 dynamics revealed that HP1 is not a stable component of heterochromatin but is highly mobile (Cheutin, T.

Visualizing telomere dynamics in living mammalian cells using PNA probes.

Chromosome ends are protected from degradation by the presence of the highly repetitive hexanucleotide sequence of TTAGGG and associated proteins. These so-called telomeric complexes are suggested to play an important role in establishing a functional nuclear chromatin organization. Using peptide nucleic acid (PNA) probes, we studied the dynamic behavior of telomeric DNA repeats in living human osteosarcoma U2OS cells.

Phosphorescent platinum/palladium coproporphyrins for time-resolved luminescence microscopy.

Streptavidin and antibodies were labeled with phosphorescent platinum and palladium coproporphyrin. The optimal conjugates were selected on the basis of spectroscopic analysis (molar extinction coefficient, quantum yield, lifetime) and using ELISA assays to determine the retention of biological activity and immunospecificity. They were subsequently tested for the detection of prostate-specific antigen, glucagon, human androgen receptor, p53, and glutathione transferase in strongly autofluorescent tissues.

Assessment of telomere length in hematopoietic interphase cells using in situ hybridization and digital fluorescence microscopy.

Telomeres are G/C-rich repetitive DNA sequences at the end of all eukaryotic chromosomes. The loss of telomeric repeat sequences during cell divisions has been proposed as a possible mechanism for cell senescence. The standard procedure for measurement of telomere length is Southern blot (SB) hybridization with a telomere-specific probe.

Platinum porphyrins as phosphorescent label for time-resolved microscopy.

We investigated phosphorescent metalloporphyrins as potential labels for time-resolved microscopy. On the basis of spectroscopic analysis of their physicochemical properties (quantum yield, molar absorption coefficient, decay times) the best candidates were selected. Next, we synthesized antibody and avidin metalloporphyrin conjugates.