Computer search of transcription control sequences in small plant virus DNA reveals a sequence highly homologous to the enhancer element of histone promoters.

The positions of nucleotide sequences which can act as binding sites for plant transcriptional trans-acting protein factors have been mapped in DNA of plant circovirus--coconut foliar decay virus (CFDV). It was found that CFDV promoter region contains sequence motif homologous to the regulatory type I element of plant histone genes. We have also found the presence of the element I motifs in DNAs of other small plant viruses. Taking into account the mechanism of regulation of histone gene expression it appears that these sequences may play a role in a cell cycle-dependent regulation of plant virus DNA transcription and replication.