text: Short-interspersed nuclear elements are transcribed by RNA polymerase III which is known to transcribe ribosomal RNA and tRNA, two types of RNA vital to ribosomal assembly and mRNA translation. SINEs, like tRNAs and many small-nuclear RNAs possess an internal promoter and thus are transcribed differently than most protein-coding genes.  In other words, short-interspersed nuclear elements have their key promoter elements within the transcribed region itself. Though transcribed by RNA polymerase III, SINEs and other genes possessing internal promoters, recruit different transcriptional machinery and factors than genes possessing upstream promoters.