No abstract

Type I interferon (IFN) was originally identified as an immunomodulatory cytokine because of its antiviral activity. Further characterization of its biological effects revealed a prominent role in the direct control of cell growth and potent immunomodulatory and antiangiogenic actions. IFN-α and IFN-ß had both been classified as type I IFN, but differences in their antitumor activities were reported. We confirmed the difference in the antiproliferative activities of IFN-α2b and IFN-ß toward HT29 and SW480 cells. IFN treatment was observed to prolong cell cycle progression; in particular, the accumulation of S-phase population was one of the most characteristic changes. The prolongation of S-phase progression and transition into G2/M-phase was suggested to be a crucial action of type I IFN on colon cancer. Additionally, IFN activated the p21 promoter gene and induced p21 WAF1/CIP1 expression. Furthermore, the cell cycle prolongation effect of IFN was suppressed when p21 expression was downregulated. Therefore, we confirmed that p21 WAF1/CIP1 was a crucial target molecule for the effects of IFN on the cell cycle. Additionally, the ability of p21 induction differed between IFN-α2b and IFN-ß and correlated with their inhibitory activities toward cell growth. We conclude that type I IFN prolongs cell cycle progression by p21 WAF1/CIP1 induction in human colon cancer cells.

No abstract

No abstract

No abstract

No abstract

No abstract

The gtjT gene and its upstream region isolated from the Streptococcus sobrinus OMZ176 chromosomal DNA were sequenced. The g(JT gene was preceded by a potential Shine-Dalgarno sequence. The g(fT gene product, glucosyltransferase (GTF), displays a typical gram-positive bacterial signal peptide sequence and both an active site peptide sequence and carboxy-terminal repeats typical of GTFs. The signal sequence is similar to those of other known GTF proteins. The putative active-site peptide sequence of this enzyme was DGIRVDAVD, which was different by one amino acid from the active-site peptide sequence derived from two different types of the S. sobyinus GTFs reported previously (G.