Fig. 5

Expression of ln-5 mRNAs in normal, quiescent, and senescent 76N breast epithelial cells. (A) Normal RNA was isolated from passage 11 76N cells at 70% confluence, quiescent RNA was from confluent passage 11 76N cells, and senescent RNA was from 70% confluent passage 22 76N cells. Ethidium bromide-stained 28S rRNA loading control is from membrane used for α3 blot and is representative of membranes used for β3 and γ2 blots. (B) Expression of ln α3 mRNA as cells become quiescent. Passage 11 76N cells were plated at 30% confluence and allowed to grow on plates for 12 days. Bars represent ln α3 expression levels assayed by Northern blotting using probe α3-A, quantified by densitometry, and normalized to 36B4 expression. (C) Expression of ln α3 mRNA as cells senesce. 76N cells at the indicated passage number were collected at 70% confluence. Expression was assayed and quantified as for Figure 5B.