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The transcription factor CREMτ and cAMP regulate promoter activity of the Na,K‐ATPase α4 isoform
Author(s) -
Rodova Marianna,
Nguyen AnhNguyet,
Blanco Gustavo
Publication year - 2006
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.20518
Subject(s) - biology , gene isoform , microbiology and biotechnology , luciferase , transcription factor , promoter , transcription (linguistics) , reporter gene , transcriptional regulation , gene , gene expression , transfection , genetics , linguistics , philosophy
Abstract The Na,K‐ATPase is an essential enzyme of the plasma membrane that plays a key role in numerous cell processes that depend on the transcellular gradients of Na + and K + . Among the various isoforms of the catalytic subunit of the Na,K‐ATPase, α4 exhibits the most limited pattern of expression, being restricted to male germ cells. Activity of α4 is essential for sperm function, and α4 is upregulated during spermatogenesis. The present study addressed the transcriptional control of the human Na,K‐ATPase α4 gene, ATP1A4 . We describe that a 5′ untranslated region of the ATP1A4 gene (designated −339/+480 based on the ATP1A4 transcription initiation site) has promoter activity in luciferase reporter assays. Computer analysis of this promoter region revealed consensus sites (CRE) for the cyclic AMP (cAMP) response element modulator (CREM). Accordingly, dibutyryl cAMP (db‐cAMP) and ectopic expression of CREMτ, a testis specific splice variant of CREM were able to activate the ATP1A4 promoter driven expression of luciferase in HEK 293 T, JEG‐3 and GC‐1 cells. Further characterization of the effect of db‐cAMP and CREMτ on deleted constructs of the ATP1A4 promoter (−339/+80, and +25/+480), and on the −339/+480 region carrying mutations in the CRE sites showed that db‐cAMP and CREMτ effect required the CRE motif located 263 bp upstream the transcription initiation site. EMSA experiments confirmed the CRE sequence as a bonafide CREMτ binding site. These results constitute the first demonstration of the transcriptional control of ATP1A4 gene expression by cAMP and by CREMτ, a transcription factor essential for male germ cell gene expression. Mol. Reprod. Dev. 73: 1435–1447, 2006. © 2006 Wiley‐Liss, Inc.