A tobacco cDNA reveals two different transcription patterns in vegetative and reproductive organs

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Silva, I. da
Angelo, P. C. S.
Molfetta, J. B.
Ferraz, M. T.
Silva, L. L. P. da
Goldman, G. H.
Goldman, M. H. S.
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In order to identify genes expressed in the pistil that may have a role in the reproduction process, we have established an expressed sequence tags project to randomly sequence clones from a Nicotiana tabacum stigma/style cDNA library. A cDNA clone (MTL-8) showing high sequence similarity to genes encoding glycine-rich RNA-binding proteins was chosen for further characterization. Based on the extensive identity of MTL-8 to the RGP-1a sequence of N. sylvestris, a primer was defined to extend the 5′ sequence of MTL-8 by RT-PCR from stigma/style RNAs. The amplification product was sequenced and it was confirmed that MTL-8 corresponds to an mRNA encoding a glycine-rich RNA-binding protein. Two transcripts of different sizes and expression patterns were identified when the MTL-8 cDNA insert was used as a probe in RNA blots. The largest is 1,100 nucleotides (nt) long and markedly predominant in ovaries. The smaller transcript, with 600 nt, is ubiquitous to the vegetative and reproductive organs analyzed (roots, stems, leaves, sepals, petals, stamens, stigmas/styles and ovaries). Plants submitted to stress (wounding, virus infection and ethylene treatment) presented an increased level of the 600-nt transcript in leaves, especially after tobacco necrosis virus infection. In contrast, the level of the 1,100-nt transcript seems to be unaffected by the stress conditions tested. Results of Southern blot experiments have suggested that MTL-8 is present in one or two copies in the tobacco genome. Our results suggest that the shorter transcript is related to stress while the larger one is a flower predominant and nonstress-inducible messenger.
Glycine-rich protein, Nicotiana tabacum, Pistil expression, RNA-binding protein, Stress conditions, Virus infection, complementary DNA, glycine, messenger RNA, RNA binding protein, controlled study, defective virus, DNA determination, DNA library, DNA probe, expressed sequence tag, flower, gene expression, gene identification, genetic transcription, genome, molecular cloning, nonhuman, Northern blotting, petal, pistil, pistil stigma, pistil style, plant disease, plant leaf, plant morphology, plant ovary, plant reproduction, plant root, plant stem, plant stress, reverse transcription polymerase chain reaction, review, sequence homology, Southern blotting, stamen, tobacco, Flowers, Gene Expression Profiling, Gene Expression Regulation, Developmental, Gene Library, Molecular Sequence Data, Nucleic Acid Hybridization, Plant Proteins, Reproduction, Reverse Transcriptase Polymerase Chain Reaction, RNA-Binding Proteins, Sequence Alignment, Sequence Analysis, Protein, Sequence Analysis, RNA, Tobacco, Nicotiana sylvestris, Tabacum, unidentified tobacco necrosis virus
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Brazilian Journal of Medical and Biological Research, v. 35, n. 8, p. 861-868, 2002.