The plastid aldolase gene fromChlamydomonas reinhardtii: Intron/exon organization, evolution, and promoter structure

Abstract

Genomic clones encoding the plastidic fructose-1,6-bisphosphate aldolase of Chlamydomonas reinhardtii were isolated and sequenced. The gene contains three introns which are located within the coding sequence for the mature protein. No introns are located within or near the sequence encoding the transit-peptide, in contrast to the genes for plastidic aldolases of higher plants. Neither the number nor the positions of the three introns of the C. reinhardtii aldolase gene are conserved in the plastidic or cytosolic aldolase genes of higher plants and animals. The 5' border sequences of introns in the aldolase gene of C. reinhardtii exhibit the conserved plant consensus sequence. The 3' acceptor splice sites for introns 1 and 3 show much less similarity to the eukaryotic consensus sequences than do those of intron 2. The plastidic aldolase gene has two tandemly repeated CAAT box motifs in the promoter region. Genomic Southern blots indicate that the gene is encoded by a single locus in the C. reinhardtii genome.

A coil–helix instead of a helix–coil motif can be induced in a chloroplast transit peptide from Chlamydomonas reinhardtii

“…Comparing several cytosol to chloroplast stroma transit peptides of nuclear‐encoded chloroplast preproteins in C. reinhardtii and their secondary‐structure predictions using the Rost–Sander method [31–34](Fig. 1[35–55]), we have selected a cTP that exhibits minimal sequence homology with the previously studied ferredoxin cTP [2], and shows the lowest level of reliability in terms of secondary‐structure prediction. The conformational properties of this peptide were investigated using CD and NMR methods to identify possible masked structural features shared with the previously studied ferredoxin cTP [2].…”

“…A lower case h indicates only a loose helix prediction with a reliability index 3–4. Ferredoxin, ferredoxin precursor [35,36]; γATPase, γ chain of ATP synthase [37]; b6f, cytochrome b6f complex 4‐kDa subunit [38]; CAB L1818, chlorophyll A‐B‐binding protein L1818 [39]; F1,6BPA, fructose bisphosphate aldolase () [40,41]; FNR, ferredoxin NADPH reductase () [42]; G3PDH, glyceraldehyde‐3‐phosphate dehydrogenase [43]; MDH NAD, NAD‐dependent malate dehydrogenase (GenBank locus CRU40465, accession number ); PRK, phosphoribulokinase [44]; PSI D, photosystem I reaction center subunit II (photosystem I 20‐kDa protein) [45]; PSI SUIV (E), photosystem I reaction center subunit IV (photosystem I 8.1‐kDa protein) [46]; PSI SUV (G), photosystem I reaction center subunit V (light‐harvesting complex I 10‐kDa protein) [47]; PSI SUVI (H), photosystem I reaction center subunit VI (light‐harvesting complex I 11‐kDa protein) [47]; PSI SUX (K), photosystem I reaction center subunit X (light‐harvesting complex I 8.4‐kDa protein) [47]; Rieske, cytochrome b6f complex iron‐sulfur subunit (Rieske iron‐sulfur protein) [48]; Rubisco Act, ribulose bisphosphate carboxylase/oxygenase activase ([49]; this study); Rubisco , ribulose bisphosphate carboxylase small chain 1 [50,51]; SBPase, sedoheptulose 1,7‐bisphosphatase [52]; Thi, thioredoxin m Ch2 [53–55].…”

Two adjacent nuclear genes are required for functional complementation of a chloroplast trans‐splicing mutant from Chlamydomonas reinhardtii

“…Both the existence of an upstream stop codon in frame with the ATG initiation site, and the correlation between predicted and observed protein size by Western blot analysis (see below), indicate that the cDNAs are full‐length clones and encode the entire protein. Two putative CAAT‐boxes are present in the 5′‐flanking region and the 3′ untranslated region (UTR) contains three putative polyadenylation signals specific for C. reinhardtii (Pelzer‐Reith et al. , 1995; Silflow, 1998).…”

Deducing Intracellular Distributions of Metabolic Pathways from Genomic Data

“…In animals, only type-! FBAs are 189 known, whereas fungi appear to rely solely on FBA IT enzymes [5). Red algae and glaucocystophytes may possess type-IT FBAs in their cytosol and type-I FBAin their plastids [6], while land plants only possess class I enzymes in plastids and cytosol.…”

“…( 4 ) Some proteins such as some nuclear components do not possess recognizable transport signals, because their transport involves their binding to and piggybacking on proteins dlat are actively in1ported into the organelle [18). (5) There are examples of fusion proteins which contain the amino acid sequence of two enzymes fused to each other; here theN-terminal enzyme usual!J de.lines the inttaceliLLiar localization [19,20).…”