TSS transcription_start_site transcription start site SO:0000315 sequence INSDC_note:transcription_start_site Added relationship is_a SO:0002309 core_promoter_element with the creation of core_promoter_element as part of GREEKC initiative August 2020 - Dave Sant. The first base where RNA polymerase begins to synthesize the RNA transcript. INSDC_feature:misc_feature primary_transcript_region core_promoter_element