Fibroblasts serum shock

Oscillations of the segmentation clock with a period of 2 h have also been observed in fibroblast cell cultures following serum shock. There also, oscillations in the expression of the gene Hesl related to the Notch pathway have been attributed to negative feedback on transcription [171]. The periodic operation of the segmentation clock was recently demonstrated in cells of the PSM, where intercellular coupling is needed to prevent damping of the oscillations [172]. 

To compare the molecular mechanisms of circadian clocks in divergent species, we cloned and analysed circadian mRNA expression of human clock genes in serum shocked fibroblasts. We also developed novel antisera and examined the temporal expression of three PER proteins (hPERl, hPER2, and hPER3). The results showed robust circadian profiles of hPER protein abundance, phosphorylation and degradation. 

Serum shock-induced circadian expression of clock genes in human fibroblasts... 

Circadian oscillation profiles of clock genes are induced in several mammalian peripheral culture cells by serum shock (Balsalobre et al 1998). To elucidate whether serum induces the circadian expression of human clock genes in normal human diploid fibroblasts, we applied RT-PCR ELISA methods to detect RNA levels of clock genes in WI-38 cells after serum stimulation (Fig. 3). Since WI-38 cells in culture invariably undergo senescence after a finite number of doublings, we selected young WI-38 cells. The RT-PCR-ELISA data are expressed as amounts (Moles) of corresponding cDNA plasmids in... 

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