Enhancement of Borna disease virus transcription in persistently infected cells by serum starvation

Transcription of Borna disease virus (BDV) in persistently infected MDCK (M DCK/BDV) cells increased in the fetal bovine serum free media as detected b y Northern blot analysis. Especially, the amount of 1.9-kb RNA without cap formation at the 5' end and polyadenylation at the 3' end, increased as com pared to other mRNA molecules of BDV. Growth arrest of MDCK/BDV cells obser ved in the condition of serum starvation might be important for increasing viral transcription. Since N-cadherin is the responsible factor for cell-to -cell contact, MDCK/BDV cells were cultured in calcium free medium which in hibits the interaction of N-cadherin. However, inhibition of cell-to-cell c ontact by N-cadherin is not effective on up regulation of viral transcripti on. Our finding in this study indicates that enhancement of BDV transcripti on by serum starvation is a useful technique for further investigation in u nderstanding of mechanisms of BDV transcription.