Alteration of the expression of a plant defensin gene by exon shuffling in bell pepper (Capsicum annuum L.).
We have characterized two members of a gene family encoding defensin-type proteins, j1-1 and j1-2. The structures of these homologous genes are highly similar. Both genes contain an intervening sequence at the same position. Sequence analysis of the intron within the j1-2 gene revealed the existence of an additional exon (exon 2ji) which also encodes a defensin-type protein. It is very likely that this exon was derived by genomic shuffling from a gene, jx, belonging to another subfamily which remains to be characterized. Only transcripts resulting from the splicing of exons 1j2 and 2ji can be detected, indicating that the inserted exon has functionally replaced the original, leaving the latter as a partial pseudogene. This rearrangement did not alter the tissue specificity of expression of the gene j1-2. The corresponding transcripts, present at the stage of fruit set, accumulate progressively during the process of development. In contrast, gene j1-1 is expressed only at the later stages of ripening. Estimates of transcription rates show that in green fruits expression is mainly regulated at a post-transcriptional level, while transcriptional regulation is prominent during ripening.
Houlné
G
G
Institut de Biologie Moléculaire des Plantes, Université Louis Pasteur, Strasbourg, France.
Meyer
B
B
Schantz
R
R
D020413:3' Untranslated Regions / Q000235:genetics; D017398:Alternative Splicing / Q000235:genetics; D000595:Amino Acid Sequence; D015152:Blotting, Northern; D002212:Capsicum / Q000235:genetics* / Q000254:growth & development; D015342:DNA Probes; D023082:Defensins; D005091:Exons / Q000235:genetics*; D005638:Fruit / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D015321:Gene Rearrangement; D007438:Introns / Q000235:genetics; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional / Q000235:genetics; D016366:Open Reading Frames / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics*; D010946:Plants, Medicinal; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D018749:RNA, Plant / Q000032:analysis / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment
D020413:3' Untranslated Regions; D015342:DNA Probes; D023082:Defensins; D010940:Plant Proteins; D012333:RNA, Messenger; D018749:RNA, Plant