The combination of a novel stimulatory element in the first exon of the maize Shrunken-1 gene with the following intron 1 enhances reporter gene expression up to 1000-fold

Maas, Christoph; Laufs, Jürgen; Grant, Sarah; Korfhage, Christian; Werr, Wolfgang

doi:10.1007/bf00020552

Cited by 171 publications

(115 citation statements)

References 32 publications

Supporting

Mentioning

109

Contrasting

Unclassified

Order By: Relevance

“…Using this construct, the number of spots in immature aleurone layers increased substantially (Figure 4d). Still, compared with aleurone layers bombarded with the pActl-F construct (McEIroy et al, 1990), which contains the promoter of the constitu- To quantify Ltp2 promoter activity in particle bombardment experiments, a second control plasmid (Maas et al, 1991) containing the LUC gene under the control of the 355 promoter was co-bombarded with the Ltp2-Gus construct. Following incubation on tissue culture medium, protein was extracted from the grains in a buffer that allowed measurement of both LUC and GUS activity (for details, see Experimental procedures).…”

Section: The Ltp2 Promoter Is Transiently Expressed Only In Developinmentioning

confidence: 99%

The promoter of the barley aleurone‐specific gene encoding a putative 7 kDa lipid transfer protein confers aleurone cell‐specific expression in transgenic rice

Kalla

Shimamoto²,

Potter³

et al. 1994

The Plant Journal

145

105

View full text Add to dashboard Cite

SummaryThis paper describes the aleurone-specific gene Ltp2 from barley, which encodes a putative 7 kDa nonspecific lipid transfer protein. As shown by Northern and in situ hybridization analyses, the Ltp2trenscript is present in barley aleurone cells shortly after the initiation of aleurone cell differentiation. The expression of Ltp2 Increases until grain mid-maturity, but the mRNA is absent from mature grains. The Ltp2 transcript is undstectable in the embryo and vegetative tissues, confirming the aleurone specificity of the Ltp2 gene. The ability of the isolated 801 bp Ltp2 promoter to direct aleurone-specific expression in immature barley grains is demonstrated by perticle bombardment experiments. In these experiments, the activity of the Ltp2 promoter is 5% of the activity of the strong constitutive Actinl promoter from rice, as quantified by GUS activity measurements. In stably transformed rice plants containing the Ltp2 promoter-Gus construct, the specificity of the Ltp2 promoter is confirmed in vivo by the presence of GUS activity exclusively in the aleurone layer. This study demonstrates the conserved nature of the regulatory signals involved in aleurone-specific gene transcription in cereal grains.

show abstract

Section: The Ltp2 Promoter Is Transiently Expressed Only In Developinmentioning

confidence: 99%

The promoter of the barley aleurone‐specific gene encoding a putative 7 kDa lipid transfer protein confers aleurone cell‐specific expression in transgenic rice

Kalla

Shimamoto²,

Potter³

et al. 1994

The Plant Journal

145

105

View full text Add to dashboard Cite

show abstract

“…The frequently observed stimulation of expression caused by plant introns has been termed intronmediated enhancement (IME) (Mascarenhas et al+, 1990)+ The difference in amount of product derived from an intron-containing gene and an otherwise identical intronless construct is typically between 2-and 10-fold but can be significantly more, especially in monocots (Maas et al+, 1991;Zhang et al+, 1994)+ The magnitude of the enhancement varies depending on the promoter, intron, and reporter gene used (Callis et al+, 1987;Luehrsen & Walbot, 1991;Rethmeier et al+, 1998), the sequences that flank the intron (Maas et al+, 1991;Clancy et al+, 1994), and the type of cell or tissue in which expression is determined (Gallie & Young, 1994)+ Even though the high degree of variability makes comparisons between studies difficult, and introns could affect expression in different ways, some common themes have emerged that help to delineate potential mechanisms of IME+ The increase in expression mediated by introns is usually apparent at the level of mRNA accumulation (Callis et al+, 1987;Dean et al+, 1989;Rethmeier et al+, 1997;Rose & Last, 1997;Wang et al+, 2002)+ However, IME is unlike the enhancement caused by transcriptional enhancer elements in that the introns must be located within transcribed sequences and in their normal orientation to boost expression (Callis et al+, 1987;Mascarenhas et al+, 1990;Clancy et al+, 1994)+ The distinction from transcriptional enhancer elements is further supported by the demonstration that the introns tested increase mRNA accumulation without significantly affecting the rate of transcript initiation, as de-termined by nuclear run-on transcription assays (Dean et al+, 1989;Rose & Last, 1997;Rose & Beliakoff, 2000)+ Although introns could elevate steady-state mRNA levels by increasing mRNA stability, the half-life of mRNA from genes with or without an intron has been reported to be the same (Nash & Walbot, 1992;Rethmeier et al+, 1997)+ Thus, the mechanism of IME remains unclear, but presumably operates at a co-or posttranscriptional level+ It is plausible that the enhancement mediated by introns is functionally connected to their recognition and removal by the splicing machinery+ Thus, the features that identify a sequence as an intron and/or participate in spliceosome assembly and the splicing reactions might also be involved in IME+ In Arabidopsis, the only recognizable characteristics of introns are that they have weakly ...…”

Section: Introductionmentioning

confidence: 99%

Requirements for intron-mediated enhancement of gene expression in Arabidopsis

Rose

2002

RNA

111

128

View full text Add to dashboard Cite

“…Positioning of the intron in the natural orientation within the 5Ј portion of the transcription unit is typically required for enhancement (Callis et al, 1987;Mascarenhas et al, 1990;Maas et al, 1991;Clancy et al, 1994;Snowden et al, 1996;Bourdon et al, 2001;Chaubet-Gigot et al, 2001), establishing that introns do not function as traditional transcriptional enhancers. Length (Sinibaldi and Mettler, 1992) and composition of flanking sequences influence the degree of stimulation (Luehrsen and Walbot, 1991;Maas et al, 1991;Clancy et al, 1994). The degree of enhancement is usually greater for relatively weak promoters (Callis et al, 1987;Vasil et el., 1987;Mascarenhas et al, 1990;.…”

mentioning

confidence: 99%

Splicing of the Maize Sh1 First Intron Is Essential for Enhancement of Gene Expression, and a T-Rich Motif Increases Expression without Affecting Splicing

2002

View full text Add to dashboard Cite

Certain plant and animal introns increase expression of protein-coding sequences when placed in the 5Ј region of the transcription unit. The mechanisms of intron-mediated enhancement have not been defined, but are generally accepted to be post-or cotranscriptional in character. One of the most effective plant introns in stimulating gene expression is the 1,028-bp first intron of the Sh1 gene that encodes maize (Zea mays) sucrose synthase. To address the mechanisms of intron-mediated enhancement, we used reporter gene fusions to identify features of the Sh1 first intron required for enhancement in cultured maize cells. A 145-bp derivative conferred approximately the same 20-to 50-fold stimulation typical for the full-length intron in this transient expression system. A 35-bp motif contained within the intron is required for maximum levels of enhancement but not for efficient transcript splicing. The important feature of this redundant 35-bp motif is T-richness rather than the specific sequence. When transcript splicing was abolished by mutations at the intron borders, enhancement was reduced to about 2-fold. The requirement of splicing for enhancement was not because of upstream translation initiation codons contained in unspliced transcripts. On the basis of our current findings, we conclude that splicing of the Sh1 intron is integral to enhancement, and we hypothesize that transcript modifications triggered by the T-rich motif and splicing may link the mRNA with the trafficking system of the cell.Most plant genes contain intervening sequences (introns) that are transcribed into pre-mRNA and later removed by splicing. Introns separate gene segments (exons) that hold protein-coding information or are non-coding but retained in the mature transcript. The observation that some introns stimulate gene expression was first made in animal systems and extended to plants when Callis et al. (1987) demonstrated that the maize (Zea mays) Adh1 first intron increased expression of several genes. Other maize introns that have been shown to increase expression include the Bz1 intron (Callis et al., 1987), Hsp82 first intron (Silva et al., 1988), Sh1 first intron (Vasil et al., 1989), Adh1 introns 2 and 6 (Mascarenhas et al., 1990), actin third intron (Luehrsen and Walbot, 1991), GapA1 first intron (Donath et al., 1995), Ubi1 first intron (Vain et al., 1996), and the RpoT fourth intron (Bourdon et al., 2001).Plant introns that stimulate expression have been documented in petunia (Petunia hybrida; Dean et al., 1989;Vain et al., 1996) Leon et al., 1991;Fu et al., 1995aFu et al., , 1995b, Arabidopsis (Rose and Last, 1997; ChaubetGigot et al., 2001), soybean (Glycine max; Kato et al., 1998), and tobacco (Nicotiana tabacum; Plesse et al., 2001). The approximately 2-to 10-fold range of intron-mediated enhancement usually seen in dicots is much less than increases observed in monocots, which can be more than 100-fold (for review, see Simpson and Filipowicz, 1996). Not all plant introns enhance gene expression. Three dicot introns do no...

show abstract

The combination of a novel stimulatory element in the first exon of the maize Shrunken-1 gene with the following intron 1 enhances reporter gene expression up to 1000-fold

Cited by 171 publications

References 32 publications

The promoter of the barley aleurone‐specific gene encoding a putative 7 kDa lipid transfer protein confers aleurone cell‐specific expression in transgenic rice

The promoter of the barley aleurone‐specific gene encoding a putative 7 kDa lipid transfer protein confers aleurone cell‐specific expression in transgenic rice

Requirements for intron-mediated enhancement of gene expression in Arabidopsis

Splicing of the Maize Sh1 First Intron Is Essential for Enhancement of Gene Expression, and a T-Rich Motif Increases Expression without Affecting Splicing

Contact Info

Product

Resources

About