Expression of cell cycle related proteins--proliferating cell nuclear antigen (PCNA) and statin--during adaptation and de-adaptation of EUE cells to a hypertonic medium.
EUE cells adapted to grow for long times in a hypertonic medium have a longer cell cycle than those growing in isotonic medium. To elucidate whether this lengthening involves specific cycle phases to differing extents, the expression of two cycle-related protein, PCNA and statin, was studied by dual parameter flow cytometry of indirect immunofluorescence protein labelling and DNA content. In isotonic medium, most cells, in all the cycle phases, were PCNA positive; in contrast, PCNA negative cells and statin positive cells were very few in number and only fell in the G0/1 range of DNA contents. In hypertonic medium, the frequency of PCNA positive cells was lower, and that of statin positive cells higher, than in isotonic medium, particularly in the G0/1 range of DNA contents: this suggests that a G0 block occurs under long-term hypertonic stress. Consistently, dual parameter flow cytometric measurement of BrdUrd immunofluorescence labelling and DNA content showed that fewer cells entered S phase in hypertonic medium and their progression through the S phase was slower; evidence was also found for the occurrence of a G2 block. These kinetics changes were fully reversible in isotonic medium, thus indicating the adaptive nature of the EUE response to hypertonicity.
Dipartimento di Biologia Animale, Pavia, Italy.
C
C
Pellicciari
M
M
Danova
M
M
Giordano
A M
AM
Fuhrman Conti
G
G
Mazzini
E
E
Wang
E
E
Ronchetti
A
A
Riccardi
M G
MG
Manfredi Romanini
D000222:Adaptation, Physiological; D002453:Cell Cycle; D018797:Cell Cycle Proteins; D002460:Cell Line; D003470:Culture Media; D004847:Epithelial Cells; D004848:Epithelium / Q000196:embryology / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D006982:Hypertonic Solutions; D007700:Kinetics; D008856:Microscopy, Fluorescence; D009687:Nuclear Proteins / Q000096:biosynthesis*; D020648:Peptide Elongation Factor 1; D018809:Proliferating Cell Nuclear Antigen; D014176:Protein Biosynthesis; D011506:Proteins
D018797:Cell Cycle Proteins; D003470:Culture Media; C503234:EEF1A2 protein, human; D006982:Hypertonic Solutions; D009687:Nuclear Proteins; D020648:Peptide Elongation Factor 1; D018809:Proliferating Cell Nuclear Antigen; D011506:Proteins