Identification of domains of c-Jun mediating androgen receptor transactivation.
The proto-oncoprotein c-Jun, when complexed with c-Fos, forms the climeric complex identified as AP-1 which regulates transcription directly by binding to AP-1-responsive genes. We have previously reported an indirect mechanism by which c-Jun is able to regulate transcription by stimulating androgen receptor transactivation in the absence of c-Fos or any apparent DNA binding. A series of c-Jun mutants were tested in order to characterize the domains of c-Jun responsible for this effect. The studies reported here indicate that a functional bZIP region and a portion of the N-terminal activation functions is necessary for c-Jun stimulation of androgen receptor transactivation. Testing c-Jun/v-Jun chimeras, we show that v-Jun is unable to stimulate androgen receptor transactivation and the effect is dependent on the c-Jun activation functions. c-Jun exhibits a bell-shaped activity on androgen receptor-mediated transactivation which appears to be distinct from c-Jun's transactivation ability. A c-Jun mutant deficient in transactivation is able to stimulate androgen receptor activity. These results indicate that c-Jun's transactivation ability can be separated from c-Jun's ability to stimulate the androgen receptor transactivation.
Wise
S C
SC
University of Toledo, Department of Biology, Ohio 43606, USA.
Burmeister
L A
LA
Zhou
X F
XF
Bubulya
A
A
Oberfield
J L
JL
Birrer
M J
MJ
Shemshedini
L
L
D000818:Animals; D050976:Basic-Leucine Zipper Transcription Factors; D019556:COS Cells; D004268:DNA-Binding Proteins / Q000502:physiology; D051790:G-Box Binding Factors; D016755:Proto-Oncogene Proteins c-jun / Q000737:chemistry / Q000502:physiology*; D011944:Receptors, Androgen / Q000502:physiology*; D011965:Receptors, Glucocorticoid / Q000502:physiology; D014157:Transcription Factors / Q000502:physiology; D015533:Transcriptional Activation
D050976:Basic-Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins; D051790:G-Box Binding Factors; D016755:Proto-Oncogene Proteins c-jun; D011944:Receptors, Androgen; D011965:Receptors, Glucocorticoid; D014157:Transcription Factors