Regulatory mechanism of the gene expression during chlorovirus infection cycle

In chlorovirus infection, immediate-early gene expression occurs within 5-20 min post infection (p.i.). We identified 16 major immediate-early transcripts. On Northern blot analysis, these transcripts showed unusual behaviors: (I) after 40 min p.i., their sizes reduced by approximately 100 nt, most likely caused by loss of a poly(A) tail and (II) after 40 min p.i., often appeared a few larger additional transcripts that may be formed by read-through from an upstream gene or into a downstream gene. These results indicate that the transcription of the viral genes changes drastically between before and after 40 min p.i.