Fig. 1.

Global microRNA transcription correlates with growth-rate in protein-free and suspension adapted CHO cell lines. (a) Five CHO cell lines were selected for cultivation in chemically defined media. Two individual batch cultivations were performed and samples were harvested during exponential and stationary growth phase. (b) For each cell line, the specific growth rate was calculated between day 1 and day 3. (c) RNA from exponential growth phase was used for miRNA microarray hybridization. Log₂ transformed fold changes in miRNA expression between each cell line and the common reference pool are shown (average from n = 2 per group). Data from DUKXB-11 Epo and CHO-K1 0 mM are not shown. (d) The relationship between miRNA transcript level and specific growth rate was analyzed by Pearson correlation. miRNAs with Pearson correlation coefficients (PCC) greater 0.8 or smaller −0.8 were filtered. Distribution of miRNAs with positive (46), negative (17) or no correlation (206) is given.