Autoregulation of mouse BMP-2 gene transcription is directed by the proximal promoter element

The prion proteins (PrP) from sheep and mouse were produced in large quantities of full-length protein in Escherichia coli after fusion with a carboxy-terminal hexahistidine sequence. Both recombinant proteins were recognized, at variable levels, in ELISA using a panel of antibodies recognizing different parts of the PrP molecules, from the octo-repeat region (79-92 human sequence), to the C terminal end of the protein. We show that these recombinant proteins enable polyclonal antisera to be produced in PrP0/0 mice, the sheep prion protein being strongly immunogenic, using either native or guanidium hydrochloride-treated recombinant protein. Sera produced against the sheep protein also reacted in Western blot with bovine, ovine, and murine PrP res, but showed higher reactivity with sheep PrP res. Interestingly, when compared to an antiserum produced against bovine 106-121 peptidic sequence (RB1), we found strikingly different ratios of the PrP res glycoforms, in both cattle with BSE and sheep with natural scrapie, but not in scrapie infected mice. Such results further demonstrate that the assessment of PrP res glycoform ratios, using different antibodies, may depend on antibodies species-specificities.     

Autoregulation of fos: the dyad symmetry element as the major target of repression.

Fos and Jun co-operatively repress the fos promoter. Removal of all putative Fos/Jun binding sites from the fos promoter neither obliterates the repression by Fos/Jun in transient cotransfection experiments in NIH3T3 cells nor the turn-off kinetics of serum-induced fos expression in stably transfected NIH3T3 cells. The dyad symmetry element (DSE) suffices to subject a promoter to this type of repression. However, one of the putative Fos/Jun binding sites (-292 to -299 and thus located immediately adjacent to the DSE), determines the very low level of basal expression.     

Characterization of transcription factors and cis-acting elements that regulate human CTP: phosphoethanolamine cytidylyltransferase (Pcyt2)

CTP: phosphoethanolamine cytidylyltransferase (Pcyt2) promoter was isolated from human breast cancer MCF-7 cells and its activity delineated by luciferase reporter assays and gel-shift analysis. The Pcyt2 promoter is driven by a functional CAAT box (-90/-73) and by negative (-385/-255) and positive regulatory elements (-255/-153) in the upstream regions.