Cloning and characterization of the tomato karyopherin α1 gene promoter

Abstract

The karyopherin ␣ 1 ( LeKAP ␣ 1) gene of tomato ( Lycopersicon esculentum ) encodes a receptor involved in nuclear import. To analyze the expression pattern of this gene, a genomic clone containing its upstream region was isolated and sequenced. To study the promoter functionality, a 2170 bp fragment (LM1), was fused to glucuronidase (GUS) and introduced into petunia cells by particle bombardment. For further characterization of the promoter, one inverse and three deletion constructs were studied in cell suspension. To follow its expression in tobacco leaves, transgenic plants expressing GUS under the control of the LM1 promoter were made. Expression of LM1-GUS was largely restricted to actively growing leaf regions, suggesting possible involvement of active cell division and plant growth regulators in LeKAP ␣ 1 expression.

Induction of karyopherin α1 expression by indole-3-acetic acid in auxin-treated or overproducing tobacco plants

“…Expression of the LeKAPα1 promoter was mainly observed in roots and in leaf veins, but was hardly visible in hypocotyls. These results, which directly show the induction of LeKAPα1 promoter by auxin, provide the molecular basis for our previous observation 20 that this promoter was expressed in plant tissues known to contain high auxin levels.…”

“…In our previous study of the LeKAPα1 gene regulation, we characterized the expression pattern of its promoter in transgenic tobacco plants. 20 The 2,170 bp fragment of the LeKAPα1 promoter (GenBank accession no. AY189742) was named LM1.…”

“…The second transgene included the reporter gene GUS fused to the promoter region, termed LM1, of LeKAPα1. 20 Studies of these plants indicated that LeKAPα1 expression occurred largely in plant areas where auxin accumulates. In the second approach, we challenged transgenic tobacco plants containing the LM1-GUS construct with different concentrations of exogenous auxin.…”

“…To study the effect of exogenous auxin on LeKAPα1 expression, we utilized the LM1-GUS transgenic plants. 20 The pattern of LeKAPα1 promoter expression was examined in LM1-GUS expressing tobacco seedlings exposed to different concentration of exogenous auxin. As shown in Figure 2, treatment of tobacco seedlings with two different auxin solutions (1 and 3 μg mL -1 ) led to a clear induction of GUS activity, indicating the expression of the LeKAPα1 promoter only in the presence of high auxin levels.…”

Multiple regions in dengue virus capsid protein contribute to nuclear localization during virus infection

“…It is possible that the differences in nuclear localization of mutated C proteins in PS and Vero cells are due to the heterogeneity and availability of carrier proteins in these mammalian cell lines, whereas no carrier protein in C6/36 cells is able to perform this function for both the wild-type and mutated C proteins. Nuclear localization of cellular proteins is partly controlled by differential expression of carrier proteins in different tissues (Nachury et al, 1998;Kohler et al, 1999;Hogarth et al, 2006), and their expression may be influenced by various cellular stimulations (Mizrachy et al, 2004;Tao et al, 2004). A situation where different carrier proteins may interact with the same cargo to facilitate nuclear localization under different conditions (Jans et al, 2000) may underlie the differences that are observed when C protein mutant viruses are tested in cell lines with differences in host species of origin, tissue type and differentiation status.…”