The gene for trypsin inhibitor CMe is regulated in trans by the lys 3a locus in the endosperm of barley (Hordeum vulgare L.)

Abstract

Summary.A cDNA encoding trypsin inhibitor CMe from barley endosperm has been cloned and characterized. The longest open reading frame of the cloned cDNA codes for a typical signal peptide of 24 residues followed by a sequence which is identical to the known amino acid sequence of the inhibitor, except for an lie/Leu substitution at position 59. Southern blot analysis of wheat-barley addition lines has shown that chromosome 3H of barley carries the gene for CMe. This protein is present at less than 2%-3% of the wild-type amount in the mature endosperm of the mutant Ris0 1508 with respect to Bomi barley, from which it has been derived, and the corresponding steady state levéis of the CMe mRNA are about 1%. One or two copies of the CMe gene (synonym Itcl) per haploid genome have been estimated both in the wild type and in the mutant, and DNA restriction patterns are identical in both stocks, so neither a change in copy number ñor a major rearrangement of the structural gene account for the markedly decreased expression. The mutation at the lys 3a locus in Ris0 1508 has been previously mapped in chromosome 7 (synonym 5H). A single dose of the wild-type alíele at this locus (Lys 3a) restores the expression of gene CMe (alíele CMe-1) in chromosome 3H to normal levéis.

Cloning of cDNA and chromosomal location of genes encoding the three types of subunits of the wheat tetrameric inhibitor of insect ?-amylase

“…IB, C). The known N-terminal sequences of the three proteins are preceded by typical signal sequences, in agreement with previous observations concerning in vitro and in vivo synthesis of these proteins [28] and with the precursor structures of other members of the family deduced from their corresponding cDNAs [16,17,29,31 ]. In Fig.…”

“…Homology was fully demonstrated both in barley and in wheat through purification of the subunits, N-terminal sequencing, and in vitro reconstitution of the inhibitory activity [2,3,11,31,34,35]. Three types of subunits, with little or no activity by themselves, are integrated into the active inhibitor: wheat proteins CM1 and CM2, encoded by genes in chromosomes 7D and 7B respectively, and barley protein CMa, whose gene is in chromosome 7H, are of the first type; wheat proteins CM16 and CM17, encoded by genes in chromosomes 4B and 4D, and barley protein CMb, encoded in chromosome 4H, are of the second type; while the third type is represented by wheat proteins CM3B and CM3D, together with its barley equivalent CMd [ 1,8,11,32,34,35].…”

A major barley allergen associated with baker's asthma disease is a glycosylated monomeric inhibitor of insect ?-amylase: cDNA cloning and chromosomal location of the gene

“…Furthermore, the sequence of BMAI-1 is closer to those of monomeric and dimeric inhibitors, such as BDAI-1 and WMAI-1 (ca. 60~o identical residues) than to any of the other proteins of this multigene family (20-45 % identical residues), such as the trypsin inhibitors and the subunits of the tetrameric inhibitors of c~-amylase [7,8,11,26].…”

A Multigene Family of Trypsin/α-Amylase Inhibitors from Cereals

“…The mutation at the Lys3a locus in Ris<| ) 1508 has been previously mapped in chromosome 5H. A single dose of the wild type alíele at this locus (Lys3a) restores the expression of gene CMe in chromosome 3H to normal levéis (Rodriguez-Palenzuela et al, 1989).…”