Fig. 5.

Analysis of differential miRNA transcription in CHO cell lines. (a) Differential expression analysis for the contrast serum-free versus serum-dependent (one-way ANOVA, p ≤ 0.05) was performed considering only miRNAs with read counts > 500. Log₂ fold changes of 18 significantly regulated miRNAs are depicted in a bubble plot, where miRNAs are sorted according to mean expression levels, represented by the bubble size. (b) The significant reduction of miR-221-3p in serum-free adapted cells was accompanied by an overall switch of the ratio of 5′ and 3′ mature miRNA levels originating from mir-221 from positive to negative, wich was restored again in recombinant cell lines. (c) Differential expression analysis of miRNAs between recombinant and serum-free CHO host-cells (one-way ANOVA, p < 0.05, read count > 500) identified 8 significantly regulated miRNAs. (d) Six out of 18 miRNAs that were found regulated between serum-free and serum-dependent growth, and 4 miRNAs that were found regulated in recombinant versus host cells were chosen for qPCR validation. Log₂ transformed fold changes for both contrasts are given as bar chart, where black bars represent log₂ fold changes as determined by sequencing and grey bars as determined by quantitative PCR.