Analysis of cis-active sequences involved in the leaf-specific expression of a potato gene in transgenic plants

Abstract

ST-LS] is a light-inducible, single-copy gene from potato that is expressed only in photosynthetic tissues. Various sequences derived from the 5'-upstream region of this gene were fused to the coding region of the chloramphenicol acetyltransferase (CAT) gene and to the gene 7 termination region of the transfer DNA (T-DNA) from the Agrobacterium Ti plasmid pTiACH5 and transferred to tobacco using Ti-plasmid vectors. After regeneration of whole plants, tissues were assayed for the expression of the CAT gene. Sequences derived from the 5'-upstream region of the ST-LS] gene comprising positions -334 to +11 were sufficient to confer a leaf/stemspecific as well as a light-inducible expression of the CAT gene. Destruction of chloroplasts by treatment with the herbicide norfluorazon and subsequent exposure to light drastically reduced the expression of the CAT gene indicating that this upstream sequence most likely interacts with a chloroplastdependent signal. When sequences from position -98 to position +675 were fused to a truncated inactive fragment of the cauliflower mosaic virus 35S promoter in a head-to-head manner, the corresponding chimeric genes were again expressed in photosynthetic tissues only, indicating that these sequences have enhancer-like properties.

Molecular dissection of GT-1 from Arabidopsis.

“…The nuclear GT-1 activity that binds to six binding sites in the upstream region of rbcS-3A was identified as one such factor . GT-1 binding sites were also found within the promoter regions of several other light-responsive genes and were shown to be involved in light-responsive transcription in vivo (Stockhaus et al, 1987;Manzara and Gruissem, 1988;Dean et al, 1989;Schindler and Cashmore, 1990). Gain-of-function experiments have confirmed the critical role of GT-1 binding sites in mediating light-responsive and tissue-specific gene expression.…”

Characterization of a gene encoding a DNA binding protein with specificity for a light-responsive element.

“…One of these factors, GT-1, binds to six binding sites present in the upstream region of rbcS-3A (Green et al, 1987(Green et al, ,1988a. Similar sequence motifs are also present within several other light-responsive genes (Stockhaus et al, 1987;Manzara and Gruissem, 1988;Dean et al, 1989;Elliot et al, 1989;Kay et al, 1989;Dehesh et al, 1990;Schindler et al, Current address: Centre for Plant Biochemistry and Biotechnology, The University of Leeds, Leeds, LS2 9JT, U.K.…”

“…It is as yet unclear whether tobacco GT-la can interact with other box Il-like elements present upstream of rbcS-3A (Green et al, 1987(Green et al, ,1988a) and other light-responsive genes (Stockhaus et al, 1987;Manzara and Gruissem, 1988;Dean et al, 1989;Elliot et al, 1989;Schindler et al, 1990;Lawton et al, 1991) or whether additional GT binding proteins exist. The characterization of rice GT-2 (Dehesh et al, 1990) and the purification of SBF-1 suggest that GT binding proteins probably comprise a small family of related factors of which tobacco GT-la is one.…”

The Regulation of Enzymes Involved in Chlorophyll Biosynthesis

“…As a consequence, further chloroplast development does not proceed. Transcripts encoding plastid proteins, such as the small subunit of ribulose-I ,5-bisphosphate carboxylase and the light-harvesting chlorophyll-db-binding proteins, as well as mRNAs for peroxisomal and other proteins related to plastid function rapidly disappear (Reiss et al, 1983;Mayfield and Taylor, 1984;Harpster et al, 1984;Oelmiiller and Mohr, 1986;Oelmuller et al, 1986aOelmuller et al, , 1988Oelmuller and Schuster, 1987) because their nuclear genes are no longer transcribed (Simpson et al, 1986;Stockhaus et al, 1987;Ernst and Schefieck, 1988;Hess et al, 1994). Similar to nortlurazon, nuclear mutations that cause carotenoid deficiency and thus ultimately lead to photooxidation of the plastid compartment negatively influence the expression of the nuclear rbcS and Zhcdb genes (Mayfield and Taylor, 1984;Batschauer et al, 1986;Burgess and Taylor, 1987).…”