Differences in intron-mediated enhancement of gene expression by the first intron of cytosolic superoxide dismutase gene from rice in monocot and dicot plants

Abstract

Introns have an enhancing e ect on gene expression known as intron-mediated enhancement in various organisms, including plants. Although the mechanism of the enhancement is largely unknown, most enhancing introns are rst introns. In this study, we examined whether the rst intron of rice superoxide dismutase sodCc2 gene has an enhancing e ect in rice and other plant species. A transient expression assay revealed that the sodCc2 intron elevated reporter gene expression in rice, wheat, and maize, but not in Arabidopsis and tobacco, indicating that the sodCc2 intron has an enhancing e ect in monocot but not in dicot plants. To nd the putative signal sequences responsible for the enhancement, we carried out an in silico search and found two motifs conserved among the sodCc2 intron and 11 enhancing introns previously known in rice. e motifs contain a consensus sequence, GATCTG, which also exists in the conserved motif found in Arabidopsis enhancing introns. Our results suggest that common motifs are conserved between rice and Arabidopsis enhancing introns.

Intron-Mediated Enhancement: A Tool for Heterologous Gene Expression in Plants?

“…The use of the CDS of gusA and, especially, the CDS of cat resulted in a stronger accumulation of RNA compared to the level of enhancement affected by the CDS of luc when IME of the ZmAdh1-S intron was studied in maize suspension cells (Luehrsen and Walbot, 1991). This effect was also observed when GUS and LUC activity was measured in transiently transformed green and etiolated rice seedlings, respectively (Morita et al, 2012). The OsSodCc2 intron led to a 17-fold enhancement of GUS activity but only to a fivefold enhancement of LUC activity.…”

“…However, the substrate luciferin had to be taken up by the plants via the root system and caused expression patterns that were mainly determined by the track of uptake and, thus, the vasculature system (Ow et al, 1986). With the exception of the studies by Chung et al (2006) and Morita et al (2012) that also used sea pansy LUC ( Renilla reniformis ) as a reporter, all other studies used firefly LUC ( Photinus pyralis ) to monitor LUC activity in transient monocot (Luehrsen and Walbot, 1991; Washio and Morikawa, 2006; Morita et al, 2012) and dicot (Norris et al, 1993) systems and in stably transformed Arabidopsis plants (Chung et al, 2006) ( Figure 2 ). However, the Renilla luc was used as an internal control in both publications.…”

Expression of a rice glutaredoxin in aleurone layers of developing and mature seeds: subcellular localization and possible functions in antioxidant defense

“…Thus, the OsGrxC2;2 coding region was fused to the downstream of the Cauliflower mosaic virus (CaMV) 35S promoter and the first intron of the rice cytosolic SOD sodCc2 gene, which enhances transgene expression in rice (Morita et al 2012). We then excised the HindIII-Sac I fragment and integrated it into the pIG121Hm T-DNA vector (Ohta et al 1990).…”

“…For the overexpression of OsGrxC2;2 in transgenic plants, we excised the entire coding region of OsGrxC2;2 from the cDNA plasmid by EcoRV and Sac I digestion, and cloned it into the Sma I and Sac I sites of p35SINTGUS (Morita et al 2012) in place of the b-glucuronidase coding sequence. Thus, the OsGrxC2;2 coding region was fused to the downstream of the Cauliflower mosaic virus (CaMV) 35S promoter and the first intron of the rice cytosolic SOD sodCc2 gene, which enhances transgene expression in rice (Morita et al 2012).…”

Recent Advancements in Gene Expression and Enabling Technologies in Crop Plants

“…The most recognized member of this group of promoters is the CaMV 35S, which controls the synthesis of the viral 35S major transcript Kay et al 1987). Although used widely, the CaMV 35S promoter performs poorly in monocotyledons such as maize (Goddijn et al 1993;Urwin et al 1997), but expression is enhanced by the addition of a downstream intron within the 5′ UTR (see intronmediated enhancement section) (Morita et al 2012). A range of promoters from other caulimoviridae members have been characterized in maize, including figwort mosaic virus (FMV;Bhattacharyya et al 2002), Cestrum yellow leaf curling virus (CmYLCV;Stavolone et al 2003), and Cassava vein mosaic virus (CsVMV; Verdaguer et al 1996).…”