Abstract
Yunis and Soreng recently demonstrated enhanced expression of common fragile sites as and of fra(X) when 2.2 mM caffeine is added to FUdR treated lymphocyte cultures 6 hours before harvest. We failed to replicate this finding for fra(X) expression in lymphocytes. However, we do find a consistent increase in expression levels in somatic cell hybrids between a Chinese hamster cell line and 3 unrelated individuals with the fra(X) mutation when caffeine is present for the last 2 hours before harvest. This was particularly true for "low-expressing" cell lines, in which a 4-6 fold increase was observed. Using a thymidylate synthase deficient hybrid which could be blocked in the S phase by thymidine deprivation, we found that caffeine significantly reduced the recovery time from thymidine release to mitosis. This produced the highest level of fra(X) expression (48%) only one hour after release from thymidine deprivation. These results show that caffeine does enhance fra(X) expression in at least some cell types. The effect is probably indirect, inhibiting the mitotic delay usually associated with DNA damage.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
