The distal transcription signals of the herpesvirus tk gene share a common hexanucleotide control sequence

Abstract

The two distal transcription signals of the herpesvirus tk gene share a common hexanucleotide sequence and function in a mutually dependent manner. We examined their roles by introducing corresponding base mutations into each hexanucleotide. The effects of mutations in the hexanucleotide of the first distal signal match the pattern of effects of the corresponding mutations in the second distal signal. These concordant patterns suggest that the hexanucleotide repeats are functionally analogous. There is one difference between the two distal signals. Disruption of the second distal signal concomitantly inactivates the first distal signal; disruption of the first distal signal leads to only partial inactivation of the second distal signal. When the positions of the two distal signals are switched, the partial dependence of the second distal signal is alleviated. We suggest a model for positive transcriptional control analogous to activation of the cl maintenance promoter of bacteriophage lambda by repressor.

A very strong enhancer is located upstream of an immediate early gene of human cytomegalovirus

“…In addition, two CCGCCC motifs are present as an inverted repeat upstream of the capping site at positions -52 to -57, and -71 to -76 (Figure 3). In herpes simplex virus, CCGCCC motifs are involved in the modulation of IE gene expression (Kristie and Roizman, 1964; and are also essential promoter components of the thymidine kinase gene (McKnight et al, 1984). In SV40, the CCGCCC sequence is present within the 21 bp repeats of the early promoter (Everett et al, 1983) and is known to bind the transcription factor Spl (Gideni et al, 1984).…”

Abundant 5 kb RNA of Human Cytomegalovirus without a Major Translational Reading Frame

“…Also no CCAAT box-like sequence was seen at the proper distance. Immediately upstream of the initiation site, the sequence is highly GC-rich; such regions have also been proven crucial for proper function in other promoters such as that of the thymidine kinase gene of herpes simplex virus (HSV) (McKnight et al, 1984). On looking for polyadenylation signals at the 3' end, the sequence AATAAA was found at positions 6258 to 6263 (Fig.…”

FT I, anovel positive myeloid-lineage-specific transcription regulatory element within the mouse myeloperoxidase gene enhancer, En 1

“…Since then, this phenomenon has been reported in many eukaryotic enhancers, where the function of the natural enhancer can be mimicked by one of such elements when multimerised and placed upstream of a test promoter (for a review see [15]). Both relative positions and orientation of the modules in the natural enhancer are not essential for the function of these so called non-stereo-specific enhancers [8]. However, there are several recent exceptions, including the mouse T cell receptor a gene enhancer [16] and the virus-inducible enhancer of the human interferon βgene [17,18], in which the function of the natural enhancer can not be reproduced by the tandem repeats of its individual modular components.…”

“…After ligation at room temperature overnight, the polymers bigger than 4 mer were purified by spin column chromatography (using Zhu JD Clontech, Sp-400 column). After filling their 3 recessive ends with Klenow fragment and dNTP, FT I polymers were cloned at Sma I site of Pt-109 vector {the firefly luciferase gene is controlled by Herpes thymidine kinase promoter spanning from -109 to +52, [8]}. The desired clones were identified by sequencing.…”