Volume 17, Number 11,
Issue of June 1, 1997
pp. 4076-4086
Copyright ©1997 Society for Neuroscience
A Novel Basal Promoter Element Is Required for Expression of the
Rat Tyrosine Hydroxylase Gene
Received Oct. 21, 1996; revised Feb. 28, 1997; accepted March 19, 1997.
Swati Patankar1,
Meredith Lazaroff2,
Sung Ok Yoon1, and
Dona M. Chikaraishi1, 2
Departments of 1 Molecular Biology and Microbiology and
2 Neuroscience, Tufts University School of Medicine,
Boston, Massachusetts 02111
Transcription of the rat tyrosine hydroxylase (TH) gene is
controlled by enhancer sequences in its 5
flanking region; these enhancers include the AP1, dyad, and cAMP response element (CRE) motifs. We show that a novel basal promoter element (
17 GCCTGCCTGGCGA
5) positioned between the TATA box and +1 works in conjunction with
the upstream AP1-dyad and CRE enhancers but cannot support transcription by itself. A mutation of this element, termed partial dyad, reduces basal expression of a reporter gene in TH-positive cell
lines and TH-negative lines but has no effect on cAMP- or KCl-induced
expression. A double mutant at positions
17 and
11 of the partial
dyad reduces transcriptional activation by 80%. Conversely, insertion
of this element into a heterologous promoter restores basal expression
to levels mediated by the native TH promoter. The partial dyad is a
novel activational element that is required for full expression of the
TH gene and may assist in the function of the AP1, dyad, and CRE motifs
and also other enhancers further upstream. Hence, the rat TH gene is
unusual in that its enhancers will not function with a heterologous
promoter but require a specific TH promoter sequence for full
activation.
Key words:
tyrosine hydroxylase;
promoter;
CRE;
TATA box;
AP1;
cAMP;
depolarization