ABSTRACT
Structural polymorphism of 5 cell differentiation stages of hepatocarcinoma-29 from ascitic fluid is detected and the morphological criteria for identification of these stages are defined on the base of optic and electron microscopy findings, cytofluorometry, and DNA cytometry. The percentage of cells at differentiation stages 4 and 5 in the tumor structure increases after hepatocarcinoma cell inoculation into the hip. Injection of a cell cycle-modulating substance to animals with tumor growth shifts the proportion of cells with various differentiation stages. The morphological criteria of 5 stages of hepatocarcinoma-29 cell differentiation can be used for prospective drug testing.
Subject(s)
Liver Neoplasms, Experimental/pathology , Animals , Antineoplastic Agents/therapeutic use , Apoptosis , Ascitic Fluid/pathology , Cell Cycle/drug effects , Cell Differentiation/drug effects , Cell Nucleus/ultrastructure , Cell Size , Citrates/pharmacology , DNA, Neoplasm/analysis , Drug Screening Assays, Antitumor , Liver Neoplasms, Experimental/drug therapy , Mice , Mice, Inbred CBA , Neoplasm Transplantation , PloidiesABSTRACT
Studies in which Drosophila melanogaster individuals carrying transgenes of animal viruses were used to analyze the action of animal viral proteins on the cell are reviewed. The data presented suggest that host specificity of viruses is determined by their proteins responsible for the penetration of the virus into the cell, while viral proteins responsible for interactions with the host cell are much less host-specific. Due to this, the model of Drosophila with its developed system of searching for genetic interactions can be used to find intracellular targets for the action of viral proteins of the second group.
ABSTRACT
Through mutational analysis in Drosopjila we have identified the gene multiple asters (mast), which encodes a new 165 kDa protein. mast mutant neuroblasts are highly polyploid and show severe mitotic abnormalities including the formation of mono- and multi-polar spindles organized by an irregular number of microtubule-organizing centres of abnormal size and shape. The mast gene product is evolutionarily conserved since homologues were identified from yeast to man, revealing a novel protein family. Antibodies against Mast and analysis of tissue culture cells expressing an enhanced green fluorescent protein-Mast fusion protein show that during mitosis, this protein localizes to centrosomes, the mitotic spindle, centromeres and spindle midzone. Microtubule-binding assays indicate that Mast is a microtubule-associated protein displaying strong affinity for polymerized microtubules. The defects observed in the mutant alleles and the intracellular localization of the protein suggest that Mast plays an essential role in centrosome separation and organization of the bipolar mitotic spindle.
