Table 2.

Summary of mechanisms underlying transcriptional regulation and latency of deltaretroviruses.

No.	Regulatory mechanism
1	Epigenetic mechanisms
2	Transcription factors acting as activators
3	Tissue-specific expression of the proviral genome
4	Viral transactivator Tax is critical for viral infectivity and pathogenesis
5	Transcription factors acting as repressors
6	Glucocorticoid hormones can modulate the induction of BLV expression and pathology
7	LTR sequence variation plays an important role in retroviral replication and modulation of viral latency
8	Host and viral ncRNA play important role in regulation of retrovirus transcription