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GC Box (gc + box)

Distribution by Scientific Domains
Life Sciences100%

Selected Abstracts

Roles of the conserved CCAAT and GC boxes of the human and mouse type II transforming growth factor-, receptor genes

MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 4 2003
Cory T. Bernadt
Abstract Embryonal carcinoma (EC) cells are used widely to study the molecular mechanisms that regulate the transcription of genes during mammalian embryogenesis. The type II transforming growth factor-, receptor (T,R-II) gene is expressed at very low levels by mouse EC cells prior to differentiation. Differentiation of EC cells results in increases of both the steady-state levels of T,R-II mRNA and the activity of the T,R-II promoter. Several cis -regulatory elements have been shown previously to regulate the T,R-II gene. This study focuses on the role of a CCAAT box and three GC boxes in the regulation of the human and mouse T,R-II promoters in EC-differentiated cells. We demonstrate that the CCAAT box and two flanking GC boxes, Sp A and Sp B, function as positive regulatory elements in the human T,R-II promoter, and that the transcription factor complex NF-Y positively regulates the human T,R-II promoter through the CCAAT box motif. We also show that the CCAAT box and the downstream GC box Sp B, which are conserved between the human and mouse promoters, behave as positive regulatory elements in the mouse T,R-II promoter. In addition, we demonstrate that the transcription factor Sp1 can bind to the Sp B GC box in vitro. Finally, we show that a GC box located 25 bp upstream of the major transcription start site of the T,R-II gene plays a minimal role in the function of the T,R-II promoter in EC-differentiated cells. Together, our studies highlight important differences and similarities in the cis -regulatory elements that regulate the human and mouse T,R-II promoters. Mol. Reprod. Dev. 65: 353,365, 2003. © 2003 Wiley-Liss, Inc. [source]

An ABA-responsive bZIP protein, OsBZ8, mediates sugar repression of , -amylase gene expression

PHYSIOLOGIA PLANTARUM, Issue 1 2003
Yi-Ching Lee
Expression of some , -amylase genes in cereals is suppressed by sugars and activated by sugar starvation. A 100-bp sugar response sequence (SRS) identified in the promoter of a rice , -amylase gene, ,Amy3, contains three essential motifs: the GC box, the G box, and the TATCCA element. To study the mechanism of sugar regulation of ,Amy3 transcription, an ABA-responsive bZIP protein, OsBZ8, which binds specifically to the G box in ,Amy3 SRS was characterized and function analysed. In sucrose-starved rice suspension cells and embryos, decline in OsBZ8 mRNA levels coincided with the induction of ,Amy3 mRNA accumulation. In vivo gain- and loss-of-function studies by transient expression assays in rice embryos revealed that OsBZ8 suppresses SRS activity through the G box and overrides the activity of an activator, OsMYBS1, which binds to the TATCCA element. Gel mobility shift assays revealed that OsBZ8 binds specifically to the G box in vitro. These studies suggest that OsBZ8 is a suppressor responsible for sugar repression of ,Amy3 expression, and OsMYBS1 is responsible for sugar starvation induced expression of ,Amy3. [source]

Roles of the conserved CCAAT and GC boxes of the human and mouse type II transforming growth factor-, receptor genes

MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 4 2003
Cory T. Bernadt
Abstract Embryonal carcinoma (EC) cells are used widely to study the molecular mechanisms that regulate the transcription of genes during mammalian embryogenesis. The type II transforming growth factor-, receptor (T,R-II) gene is expressed at very low levels by mouse EC cells prior to differentiation. Differentiation of EC cells results in increases of both the steady-state levels of T,R-II mRNA and the activity of the T,R-II promoter. Several cis -regulatory elements have been shown previously to regulate the T,R-II gene. This study focuses on the role of a CCAAT box and three GC boxes in the regulation of the human and mouse T,R-II promoters in EC-differentiated cells. We demonstrate that the CCAAT box and two flanking GC boxes, Sp A and Sp B, function as positive regulatory elements in the human T,R-II promoter, and that the transcription factor complex NF-Y positively regulates the human T,R-II promoter through the CCAAT box motif. We also show that the CCAAT box and the downstream GC box Sp B, which are conserved between the human and mouse promoters, behave as positive regulatory elements in the mouse T,R-II promoter. In addition, we demonstrate that the transcription factor Sp1 can bind to the Sp B GC box in vitro. Finally, we show that a GC box located 25 bp upstream of the major transcription start site of the T,R-II gene plays a minimal role in the function of the T,R-II promoter in EC-differentiated cells. Together, our studies highlight important differences and similarities in the cis -regulatory elements that regulate the human and mouse T,R-II promoters. Mol. Reprod. Dev. 65: 353,365, 2003. © 2003 Wiley-Liss, Inc. [source]