Organ-Specific Occurrence and Expression of the Isoforms of Nonspecific Lipid Transfer Protein in Castor Bean Seedlings, and Molecular Cloning of a Full-Length cDNA for a Cotyledon-Specific Isoform1

Abstract

Four kinds of nonspecific lipid transfer proteins (nsLTP) were purified from different organs of castor bean (Ricinus communis L.) seedlings. Amino acid compositions and amino-terminal sequences of the four nsLTPs were determined and compared with those of castor bean isoforms, nsLTP-A, -B, and -C, previously reported [Takishima et al. (1986) Biochim. Biophys. Acta 870, 248-255; Takishima et al. (1988) Eur. J. Biochem. 177, 241-249]. Two isoforms from the cotyledons were identified as nsLTP-A and -C, one isoform from the endosperms as nsLTP-B, and the other was a new isoform from the axes. This new isoform was named nsLTP-D and its amino acid sequence was determined. These results demonstrated organ-specific occurrence of the nsLTP isoforms in castor bean seedlings. The isoforms nsLTP-A, -B, -C, and -D showed similar transfer activity not only for phosphatidylcholine and phosphatidylethanolamine but also for monogalactosyldiacylglycerol, although the homology among their amino acid sequences ranged from 70 to 30%. Two cDNA clones (pnsLTP-C and pnsLTP-D) for nsLTPs of castor bean seedlings were isolated and sequenced. pnsLTP-C was the cDNA clone for nsLTP-C expressed in the cotyledons, and pnsLTP-D was that for nsLTP-D in the axis. A coupled in vitro transcription-translation analysis of both cDNA clones revealed that pnsLTP-C encodes the full-length of nsLTP-C precursor (pro-nsLTP-C), while pnsLTP-D encodes a part of nsLTP-D precursor. PronsLTP-C contained a 24-amino acid pre-sequence preceding the mature nsLTP-C (92 amino acids).(ABSTRACT TRUNCATED AT 250 WORDS)

Four 9‐kDa proteins excreted by somatic embryos of grapevine are isoforms of lipid‐transfer proteins

“…In contrast, it is consistent with the observations of Douady et al [ 101 and Kader et al [ l l ] who found that after carboxymethyl-Sepharose chromatography, the lipid-transfer activity from maize seeds and spinach-leaf extracts were detected in two and three groups of fractions, respectively. The existence of LTP isoforms has recently been confirmed by Arondel et al 1291 who described the presence of multiple LTP-encoding mRNA and by Tsuboi et al [25] who purified four organ-specific isoforms of LTP from castor-bean seedlings.…”

Developmental Patterns of Enzymes and Proteins During Mobilization of Endosperm Stores in Germinating Barley Grains

“…LTP from maize, castor bean, spinach, tobacco, and carrot are, as barley LTP, synthesized as preproteins (MUNDY and ROGERS 1986;TCHANG et al 1988;BERNHARD, et al 1991;STERK et al 1991;TSUBOI et al 1991;FLEMING et al 1992;WEIG and KOMOR 1992). Barley LTP is co-translationally transferred across the membrane of the endoplasmic reticulum concomitant with signal peptide cleavage, and signal peptide cleavage can also occur post-translationally (MADRID 1991 b).…”

Tissue-Specific Expression of a Gene Encoding a Cell Wall-Localized Lipid Transfer Protein from Arabidopsis

“…A fourth EST with significant but lower homology to LTPl may represent the product of a third gene in Arabidopsis. LTP isoforms have also been found in castor bean (Tsuboi et al, 1991), barley (Mundy and Rogers, 1986;Linnestad et al, 1991), tobacco (Koltunow et al, 1990;Fleming et al, 1992), and wheat (Dieryck et al, 1992), and Southern analysis suggests the presence of severa1 LTP genes in maize (Tchang et al, 1989) and tomato (Torres-Schumann et al, 1992).…”