Transcription of human 5S rRNA genes is influenced by an upstream DNA sequence

Six human 5S rRNA genes and gene variants and one pseudogene have been sequenced. The six genes/variants were transcribed in a HeLa cell extract with about equal efficiency. Three genes contain the Sp1 binding sequence GGGCGG in position -43 to -38 and three genes contain the Sp1 like sequence GGGCCG in this position. The six genes contain furthermore one Sp1 binding site in a position about -245 and one ATF recognition site in a position about -202. A 12 bp sequence (GGCTCTTGGGGC) found in position -32 to -21 strongly influenced the transcriptional efficiency in vitro. This 12-mer, designated the D box, has also been found upstream a 5S rRNA gene from hamster and mouse. Removal of the Sp1 binding sites had no effect on the transcription in vitro whereas the transcriptional efficiency decreased to 10% if the D box was removed from the human 5S rRNA gene.