cry IA(b) transcript formation in tobacco is inefficient

Abstract

Chimaeric PCaMV35Scry genes direct in tobacco mesophyll protoplasts mRNA levels of less than one transcript per cell. We provide evidence that this low cytoplasmic cry IA(b) mRNA level is not due to a rapid turnover but rather results from a marginal import flow of cry messenger into the cytoplasm. Run-on assays indicate that the frequency of transcription initiation is not limiting. However, the cry precursor mRNA carries at least three regions that are recognized as introns. The absence of high cytoplasmic levels of spliced cry mRNAs suggests that these mRNAs are unstable and/or not efficiently made. Point mutations in the 5' splice site of the most distal intron allows high accumulation levels of the full-length mRNA. This implies that the inefficient formation of full-size mRNA is a major cause of the low expression level of chimaeric cry IA(b) genes in tobacco.

Transformation of Virus-Resistant Genotype of Gossypium hirsutum L. with Pesticidal Gene.

“…The distance was set at 22 cm between filter assembly and target tissue. Agrobacterium strain C58 used in this work was harboring Bt insecticidal crylAb gene & NPT II marker gene (Aarssen et al, 1995). This vector (p2845) is containing the Bt gene driven by CaMV 35S promoter (Fig.…”

Premature Polyadenylation at Multiple Sites within aBacillus thuringiensis Toxin Gene-Coding Region1

“…Alternatively, the problem may occur posttranscriptionally (Fischhoff et al, 1987;Vaeck et al, 1987;Oakes et al, 1991) as a result of aberrant splicing and/or degradation of the transcript. Recently, the transcripts of GFP and a cryIA(b) B.t.-toxin gene were found to contain one and three cryptic introns, respectively (Haseloff and Amos, 1995;Van Aarssen et al, 1995;Haseloff et al, 1997). The splicing of these transcripts was shown to be partly responsible for the low expression of the GFP and cryIA(b) genes in plants.…”

Transformation of Cotton (Gossypium hirsutum L.) With Insect Resistant Gene by Particle Bombardment and Agrobacterium

“…It harbors two genes, the neomycin phosphotransferase gene (NPT-II) which confer resistance to kanamycin regulated by Nos promoter and insecticidal cry1A(b) gene controlled by CaMV35S promoter (Van Aarssen et al,1995).…”