ABSTRACT
We have examined the effects of inhibition of the 26S proteasome in a murine mammary cell line, KIM-2 cells using the peptide aldehyde inhibitor MG132. These studies have demonstrated a clear requirement for proteasome function in cell viability. Induction of apoptosis was observed following MG132 treatment in KIM-2 cells and this death was shown to be dependent on the cell actively traversing the cell cycle. KIM-2 cells were generated using a temperature sensitive T-antigen (Tag) and studies at the permissive temperature (33 degrees C) have shown that a Tag binding protein was essential for this apoptotic response. Studies in two additional cell lines, HC11, which is a mammary epithelial cell line carrying mutant p53 alleles and p53 null ES cells suggest that p53 is actively required for the apoptosis induced as a consequence of proteasome inhibition. These results suggest a pivotal role for the 26S proteasome degradation pathway in progression through the cell cycle in proliferating cells.
Subject(s)
Apoptosis/physiology , Leupeptins/pharmacology , Mammary Glands, Animal/cytology , Protease Inhibitors/pharmacology , Proteasome Inhibitors , Tumor Suppressor Protein p53/physiology , Animals , Annexin A5/analysis , Antigens, Viral, Tumor/biosynthesis , Antigens, Viral, Tumor/physiology , Apoptosis/drug effects , Blotting, Western , Cell Cycle/drug effects , Cell Cycle/physiology , Cell Line , Cell Line, Tumor , Cell Survival/drug effects , Cell Survival/physiology , Dose-Response Relationship, Drug , Mammary Glands, Animal/drug effects , Mammary Glands, Animal/enzymology , Mice , Proteasome Endopeptidase Complex , Tumor Suppressor Protein p53/biosynthesis , Tumor Suppressor Protein p53/deficiency , Tumor Suppressor Protein p53/geneticsSubject(s)
Mammary Glands, Animal/growth & development , Mammary Glands, Animal/metabolism , Animals , Female , Gene Expression Regulation, Developmental , Lactation/genetics , Mice , Milk Proteins/biosynthesis , Milk Proteins/genetics , Polymerase Chain Reaction/methods , Pregnancy , Time Factors , Transcription, GeneticABSTRACT
Infertility and abortion caused by Campylobacter fetus is described in a series of 12 herds in South West Scotland during the period May 1974 to December 1976. Herd studies show that 44 bulls were involved and that there were 34 bull and 18 cow movements for breeding purposes. The need to include C fetus infection in the differential diagnosis of herd infertility is emphasised.