Subcellular phototoxicity of Photofrin-II and lutetium texaphyrin in cells in vitro
LASERS IN MEDICAL SCIENCE
Authors: Liang, H; Shin, DS; Lee, YE; Nguyen, DC; Kasravi, S; Do, T; Aurasteh, P; Berns, MW
Abstract
Three cell types including bovine pulmonary artery endothelium cells (CPAE), rat kangaroo kidney cells (PTK2), and human larynx epidermoid carcinoma cells (Hep-2) were used to study subcellular localisation and phototoxicity of Photofrin-II and lutetium texaphyrin (Lu Tex). Cells were examined for fluorescence after administration of the photosensitisers. Subcellular regions were exposed with a laser microbeam system that used an argon ion laser pumped dye laser generating a 630 nm for Photofrin-II and 730 nm for Lu Tex. Fluorescence detection suggests that the Photofrin-II is bound primarily to the mitochondria with some diffuse fluorescence in the rest of the cytoplasm. The fluorescence in Lu Tex treated cells appears to be localised to the lysosomes. The percentage of damaged cells following light exposure to the different subcellular regions after Photofrin-II or Lu Tex treatment demonstrates that the nuclear region was the most sensitive target followed by the perinuclear region and peripheral cytoplasm region.
THE 190-KDA CENTROSOME-ASSOCIATED PROTEIN OF DROSOPHILA-MELANOGASTER CONTAINS 4 ZINC-FINGER MOTIFS AND BINDS TO SPECIFIC SITES ON POLYTENE CHROMOSOMES
JOURNAL OF CELL SCIENCE
Authors: WHITFIELD, WGF; CHAPLIN, MA; OEGEMA, K; PARRY, H; GLOVER, DM
Abstract
Microinjection of a bacterially expressed, TRITC labelled fragment of the centrosome-associated protein CP190 of Drosophila melanogaster, into syncytial Drosophila embryos, shows it to associate with the centrosomes during mitosis, and to relocate to chromatin during interphase. Indirect immunofluorescence staining of salivary gland chromosomes of third instar Drosophila larvae, with antibodies specific to CP190, indicate that the protein is associated with a large number of loci on these interphase polytene chromosomes. The 190 kDa CP190 protein is encoded by a 4.1 kb transcript with a single, long open reading frame specifying a polypeptide of 1,096 amino acids, with a molecular mass of 120 kDa, and an isoelectric point of 4.5. The central region of the predicted amino acid sequence of the CP190 protein contains four CysX(2)CysX(12)HisX(4)His zinc-finger motifs which are similar to those described for several well characterised DNA binding proteins. The data suggest that the function of CP190 involves cell cycle dependent associations with both the centrosome, and with specific chromosomal loci.