Transcriptional analyses of the gene region that encodes human histidyl-tRNA synthetase: identification of a novel bidirectional regulatory element.
A recombinant phage clone containing the 5' end of the gene HRS encoding human histidyl-tRNA synthetase (HRS) has been isolated. Primer extension analyses indicated that there are two types of HRS transcripts. The longer transcripts were initiated from a single transcription start point (tsp) located approximately 455 bp upstream and the shorter transcripts were initiated from multiple tsp located approximately 38 to 82 bp upstream from the HRS ATG start codon. Functionally, we have identified two regions (+1 to -122; -185 to -502), each of which when placed 5' of a promoterless cat construct can initiate transcription in both orientations after transfection into HeLa cells. A pair of imperfect inverted repeats (IIR) was located within the region +1 to -122. Using mobility shift assays, we have identified a nuclear factor that binds specifically to each half of the IIR. However, this pair of IIR (-73 to -110) was not sufficient for bidirectional transcription activity. At least one copy of a 27-bp oligodeoxyribonucleotide (oligo), which spans -94 to -120, was required in order to facilitate bidirectional transcription activity. From mobility shift assays using HeLa cell nuclear extracts and this 27-bp oligo, we have identified two DNA-protein complexes, both of which are presumably required to initiate bidirectional transcription.
Tsui
H W
HW
Department of Medicine, Toronto Hospital, Ontario, Canada.
Mok
S
S
de Souza
L
L
Martin
A
A
Tsui
F W
FW
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D006224:Cricetinae; D004247:DNA; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D006643:Histidine-tRNA Ligase / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid; D014158:Transcription, Genetic; D014162:Transfection
D004268:DNA-Binding Proteins; D012333:RNA, Messenger; D004247:DNA; D006643:Histidine-tRNA Ligase