TY - JOUR
T1 - Multiple 5'-untranslated exons in the nuclear respiratory factor 1 gene span 47 kb and contribute to transcript heterogeneity and translational efficiency
AU - Huo, Lei
AU - Scarpulla, Richard C.
N1 - Funding Information:
This work was supported by United States Public Health Service Grant GM32525-17 from the National Institutes of Health. We thank Ronald Herzig and Dr Ulf Andersson for critical reading of the manuscript.
PY - 1999/6/11
Y1 - 1999/6/11
N2 - Nuclear respiratory factor 1 (NRF-1) is a nuclear transcription factor that has been implicated in the nuclear control of respiratory chain expression in mammalian cells. Here, we demonstrate that a complex pattern of alternative splicing contributes to sequence heterogeneity within the human NRF-1 5'-untranslated region (UTR). At least six different 5'-UTR exons (UTRs 1-6) were detected in NRF-1 transcripts. These exons were mapped to human NRF-1 genomic clones and their sequences, including donor and acceptor splice junctions, determined. Two of the human UTR exons were derived from insertions of Alu-sq family members into the NRF-1 locus. The distance between the transcription initiation sites in UTR1 and the first protein coding exon is approx. 47 kb, bringing the total length of the human NRF-1 gene to approx. 104 kb. In contrast to human, only two UTR exons were found in mouse. The mouse UTR1 sequence obtained is identical to human UTR1, but mouse UTR2 bears no resemblance to any of the human exons. Mutations within human UTR1 modulate NRF-1 expression by interfering with mRNA translational efficiency in transfected cells and in an in vitro translation system. The effects of the mutations are proportional to their ability to disrupt predicted mRNA secondary structures within UTR1. Thus, the unusually high sequence conservation within UTR1 in part reflects selective constraints on translational expression.
AB - Nuclear respiratory factor 1 (NRF-1) is a nuclear transcription factor that has been implicated in the nuclear control of respiratory chain expression in mammalian cells. Here, we demonstrate that a complex pattern of alternative splicing contributes to sequence heterogeneity within the human NRF-1 5'-untranslated region (UTR). At least six different 5'-UTR exons (UTRs 1-6) were detected in NRF-1 transcripts. These exons were mapped to human NRF-1 genomic clones and their sequences, including donor and acceptor splice junctions, determined. Two of the human UTR exons were derived from insertions of Alu-sq family members into the NRF-1 locus. The distance between the transcription initiation sites in UTR1 and the first protein coding exon is approx. 47 kb, bringing the total length of the human NRF-1 gene to approx. 104 kb. In contrast to human, only two UTR exons were found in mouse. The mouse UTR1 sequence obtained is identical to human UTR1, but mouse UTR2 bears no resemblance to any of the human exons. Mutations within human UTR1 modulate NRF-1 expression by interfering with mRNA translational efficiency in transfected cells and in an in vitro translation system. The effects of the mutations are proportional to their ability to disrupt predicted mRNA secondary structures within UTR1. Thus, the unusually high sequence conservation within UTR1 in part reflects selective constraints on translational expression.
KW - Alu elements
KW - Human gene
KW - Mitochondria
KW - Regulation
KW - Splicing
KW - Transcription factor
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U2 - 10.1016/S0378-1119(99)00135-3
DO - 10.1016/S0378-1119(99)00135-3
M3 - Article
C2 - 10375638
AN - SCOPUS:0032791893
SN - 0378-1119
VL - 233
SP - 213
EP - 224
JO - Gene
JF - Gene
IS - 1-2
ER -