Continuous expression in tobacco leaves of a Brassica napus PEND homologue blocks differentiation of plastids and development of palisade cells
2005 (English)In: The Plant Journal, ISSN 0960-7412, E-ISSN 1365-313X, Vol. 44, no 1, 1-15 p.Article in journal (Refereed) Published
Brassica napus complementary deoxyribonucleic acid (cDNA) clones encoding a DNA-binding protein, BnPEND, were isolated by Southwestern screening. A distinctive feature of the protein was a bZIP-like sequence in the amino-terminal portion, which, after expression in Escherichia coli, bound DNA. BnPEND transcripts were present in B. napus roots and flower buds, and to a lesser extent in stems, flowers and young leaves. Treatment in the dark for 72 h markedly increased the amount of BnPEND transcript in leaves of all ages. Sequence comparison showed that BnPEND was similar to a presumed transcription factor from B. napus, GSBF1, a protein deduced from an Arabidopsis thaliana cDNA (BX825084) and the PEND protein from Pisum sativum, believed to anchor the plastid DNA to the envelope early during plastid development. Homology to expressed sequence tag (EST) sequences from additional species suggested that BnPEND homologues are widespread among the angiosperms. Transient expression of BnPEND fused with green fluorescent protein (GFP) in Nicotiana benthamiana epidermal cells showed that BnPEND is a plastid protein, and that the 15 amino acids at the amino-terminal contain information about plastid targeting. Expression of BnPEND in Nicotiana tabacum from the Cauliflower Mosaic Virus 35S promoter gave stable transformants with different extents of white to light-green areas in the leaves, and even albino plants. In the white areas, but not in adjacent green tissue, the development of palisade cells and chloroplasts was disrupted. Our data demonstrate that the BnPEND protein, when over-expressed at an inappropriate stage, functionally blocks the development of plastids and leads to altered leaf anatomy, possibly by preventing the release of plastid DNA from the envelope.
Place, publisher, year, edition, pages
2005. Vol. 44, no 1, 1-15 p.
PEND, plastid, plastid DNA, DNA binding, plastid development, plastid envelope, protein secondary structure, dna-binding-specificity, amino-acid-sequence, nicotiana-tabacum-l, envelope membrane, nuclei nucleoids, chloroplast dna, gene-expression, coiled coils, arabidopsis
IdentifiersURN: urn:nbn:se:kth:diva-15051ISI: 000231952000001OAI: oai:DiVA.org:kth-15051DiVA: diva2:333092
QC 201005252010-08-052010-08-05Bibliographically approved