An erythrocyte-specific protein that binds to the poly(dG) region of the chicken beta-globin gene promoter.

Abstract

The promoter region of the chicken aduh p-globin gene contains a sequence of 16 deoxyguanosine residues located at a nucleosome boundary in tissues where the gene is inactive. In definitive erythrocytes that express the p-globin gene, the nucleosome is displaced, the G-string and adjacent sequences are occupied by sequencespecific DNA-binding proteins, and a nuclease hypersensitive domain is generated in this region. To gain insight into the role of the G-string in this series of events, we have examined the proteins that bind to it. Using the gel mobility shift assay and a monoclonal antibody that blocks specific binding to the G-string, we have identified a specific protein, BGPl, that is found only in chicken erythroid cells and appears at the same time, or shortly before, the changes in chromatin structure. The antibody interacts strongly with BGPl and cross-reacts weakly with Spl. Although both BGPl and Spl require Zn^+ for their DNA-binding activity, these proteins differ in their binding-site specificities, chromatographic properties, and molecular weights. In contrast to Spl, which is found in a wide variety of cell types, BGPl is restricted to erythrocytes and is most abundant in definitive erythrocytes. Thus, its presence corresponds to the tissue-and stage-specific occupancy of the G-string in vivo.

Identification of a key regulatory element for the basal activity of the human insulin-like growth factor II gene promoter P3

“…Secondly, the Zn# + requirement for DNA binding of proteins 4 and 5 suggests that these two proteins could be zinc-finger transcription factors. Interestingly, the requirement for bivalent ions has also been shown for the G-string-binding factor BGP1, which needs Zn# + ions for its DNA-binding activity [23]. Furthermore it was shown that the sea-urchin G-string-binding factor suGF1 is also tightly complexed with a cation [26].…”

“…In the chicken, two G-string-element-containing promoters have been described that are bound by the chicken erythrocyte protein called β-globin protein 1, BGP 1 [23,24]. In the sea urchin (Psammechinus miliaris) the purification of another G-stringbinding protein of 59.5 kDa, called sea-urchin G-string factor 1 (suGF1), has been described [25,26].…”

Discrimination among potential activators of the beta-globin CACCC element by correlation of binding and transcriptional properties.

“…We have found that the DNA-binding activity of CACD is inhibited by chelators of divalent cations and that low concentrations of zinc can restore binding activity (23a). The zinc-dependent DNA-binding activity of CACD is reminiscent of that demonstrated for several zinc finger proteins, including Spl and an activity, likely to be Spl, that binds the chicken CACCC element (28,34).…”

“…For these reasons, many laboratories have been interested in characterizing potential transcriptional regulatory proteins that bind to this sequence element. A number of such putative factors have been identified in many different cell types (4,8,9,17,21,34,35,38,47,55). Because we are interested in the regulation of 3-globin gene transcription, we have studied CACCC-binding proteins from MEL cells, a mouse erythroid precursor immortalized at the pre-erythroblast stage (36).…”

Purification and characterization of p27, a protein from hepatocyte chromatin Evidence suggesting that it binds selectively to guanine‐rich single‐stranded DNA

“…A mouse hepatic nuclear protein, sTBP, similarly binds to a single-stranded telomeric sequence [16]. The chicken erythrocyte protein, BGP1, binds with a high affinity to single-stranded, guanine-rich tracts within the regulatory region of the flA globin gene [17]. Recently we purified a protein, termed QUAD, from rabbit liver chromatin, that binds specifically to the quadruplex form of the Here we report the isolation of a new protein from rabbit hepatocyte, designated p27, that binds preferentially to single-stranded, guanine-rich DNA but not to its double-or tetrahelical forms.…”