Author
Submitted to: Gene Regulation and Systems Biology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 12/23/2007 Publication Date: 3/15/2008 Citation: Li, C., Li, R.W. 2008. Butyrate Induced Cell Cycle Arrest in Bovine Cells through Targeting Gene Expression relevance to DNA Replication Apparatus. Gene Regulation and Systems Biology. 2:113-123. Interpretive Summary: The objective of this study is to understand the mechanisms by which butyrate induces arrest of cell growth. Because DNA replication is the basic requirement for cell to grow, we used both real-time RT-PCR and Western blot analysis to see if DNA replication related genes have any changes in their expression after treatment with butyrate. From the quantitative RT-PCR, of five genes that we tested, CDKN1A (p21)expressed more message-RNA after treatment with butyrate, CDC2/cdk1, MCM6, ORC1L were down regulated and expressed less message-RNA. However, expression of ORC3L did not change after butyrate treatment. As consistent with RT-PCR results, Western blot analyses confirm that the cyclin-kinase inhibitor p21 protein was increased after butyrate treatment. This up-regulation of p21 was dose-dependent. In contrast, butyrate treatment has not effect on expression of ERK 1/2 proteins. Also consistent with message-RNA results, ORC1 and MCM3 proteins were decreased after butyrate treatment. ORC2 protein does not change as result of butyrate treatment. The present results suggest that ORC1, not ORC2 or ORC3, along with MCM proteins are the targets of the butyrate regulation and play a critical role in regulating cell growth. Technical Abstract: Using both real-time RT-PCR and Western blot analysis in bovine kidney epithelial cells, we systematically investigated the gene expression relevance to DNA replication apparatus targeted by butyrate. The real-time PCR and Western blot data generally confirmed the microarray analysis. From the quantitative RT-PCR, of five genes that we tested, CDKN1A (p21) was up regulated by butyrate, CDC2/cdk1, MCM6, ORC1L were down regulated. However, ORC3L did not change the expression upon butyrate treatment. As consistent with RT-PCR results, Western blot analysis confirm that butyrate up-regulated the cyclin-kinase inhibitor p21waf1. This up-regulation of p21waf1 was dose-dependent. In contrarst, butyrate treatment had no effect on expression of ERK 1/2 proteins. Also consistent with mRNA results, ORC1 and MCM3 proteins were down-regulated by butyrate treatment. ORC2 protein does not change the expression level as result of butyrate treatment. The present results suggest that ORC1, not ORC2 or ORC3, along with MCM proteins played a critical role in regulating initiation of DNA replication and cell cycle progression in MDBK cells and they are the targets of the butyrate regulation. |