Characterization of an up-stream promoter directing extrapituitary expression of the human prolactin gene.

Abstract

The human PRL gene is expressed outside pituitary lactotrophs in decidualized endometrium and lymphoid cells, but here the mRNA contains a 5'-untranslated region from an additional noncoding exon 1a. We have isolated a genomic DNA clone containing human PRL exon 1a with 2800 basepairs (bp) of 5'-flanking sequences. Sequencing locates exon 1a -5840 bp up-stream of the pituitary start site. To study its suspected regulatory function, various lengths of the 5'-flanking region were linked to the luciferase (Luc) reporter gene. Their ability to direct gene expression has been analyzed in transfection studies. The proximal 1620 bp of promoter sequence directed Luc expression in the T-lymphoid Jurkat cell line, and this was unaffected by 5'-deletion to the proximal 453 bp. However, further 5'-deletion to the most proximal 67 bp drastically reduced this activity by 90%. The exon 1a promoter was inactive in pituitary GH3 cells and HeLa cells; in contrast, the exon 1b pituitary promoter, active in GH3 cells, was inactive in Jurkat cells. DNase-I footprinting studies and further 5'- and 3'-deletion analysis identified factor-binding sites within an enhancer element located at -375/-212 bp, which contributed approximately 50% of the promoter activity.

Structure of the Human Sarco/Endoplasmic Reticulum Ca2+-ATPase 3 Gene

“…The 5Ј-end of each of the deletion constructs was confirmed by sequencing. The human SERCA3 promoter-luciferase constructs and the unmodified, promoterless pGL3 basic reporter vector were used for transient transfection of the human cell line Jurkat E6.1 cells by electroporation as described (34). To evaluate transfection efficiencies, the cells were co-transfected with 150 or 500 ng of a pEL1-␤gal vector, containing the ␤-galactosidase reporter gene driven by the elongation factor 1 promoter (pEL1-␤gal vector is a gift from Dr. F. Bulens).…”

Human Cytomegalovirus Infection Induces High Expression of Prolactin and Prolactin Receptors in Ovarian Cancer

“…Recent findings demonstrate that PRL production is not only restricted to the pituitary gland [40], which makes this theory interesting. In humans, there is a specific gene promoter allowing for PRL production in extra-pituitary locations [41], which implies that PRL not only functions as a regular hormone but potentially also as a local growth factor. Activation of the PRLR by PRL leads to activation of the JAK/STAT pathway [39,42].…”

Cyclic AMP-induced Forkhead Transcription Factor, FKHR, Cooperates with CCAAT/Enhancer-binding Protein β in Differentiating Human Endometrial Stromal Cells

“…Expression of PRL, under control of the tissuespecific decidual PRL (dPRL) promoter (3,6), by ES cells coincides with decidual differentiation and is widely used as a biochemical marker of this process (2)(3)(4)(5)7). Previous studies have shown that CCAAT/enhancer-binding protein ␤ (C/ EBP␤), a member of the C/EBP subfamily of basic region/ leucine zipper transcription factors, is induced during ES cell differentiation (4).…”