Ethylene-regulated gene expression: molecular cloning of the genes encoding an endochitinase from Phaseolus vulgaris.

Abstract

A full-length copy of bean leaf chitinase mRNA has been cloned. The 1146-base-pair insert of pCH18 encodes the 27-residue amino-terminal signal peptide of the precursor and 301 residues of the mature protein. Utilizing pCH18 as a hybridization probe, we have shown that the increase in translatable chitinase mRNA seen upon ethylene treatment of bean seedlings is due to a 75-to 100-fold increase in steady-state mRNA levels. Southern blot analysis of bean genomic DNA revealed that chitinase is encoded by a small, multigene family consisting of approximately four members. From our nucleotide sequence analysis of five additional chitinase cDNA clones, it appears that at least two of these genes are expressed. Three of the bean chitinase genes have been isolated from a Sau3A genomic library and partially characterized.The development of disease resistance in higher plants is manifested by the accumulation of a number of host-synthesized polypeptides that are produced in response to pathogen attack. Among these are the following: (i) enzymes involved in the synthesis of phytoalexins (secondary metabolites that are toxic to bacteria and fungi) (1), (ii) enzymes leading to the formation of physical barriers to fungal invasion through modifications of the plant cell wall (2), (iii) inhibitors of serine endoproteases (2, 3), and (iv) lytic enzymes (e.g., chitinase and ,-1,3-glucanase) that are capable of degrading fungal cell walls (4,5). While inhibitor studies indicate that host RNA and protein synthesis are required for the induction of these proteins (6), there is a paucity of information concerning the regulation and expression of the genes involved.

Intracellular Localization of a Class IV Chitinase from Yam

“…Furthermore, this yam chitinase has an additional 8 amino acids (the C-terminal extension) following the last cysteine at the C-terminal, compared with other class IV chitinases. 9) With respect to the Cterminal extension, some class I chitinases have been found in bean, 23) potato, 24) tobacco, 25) rice 26,27) and grape 28) to have a C-terminal extension like this yam class IV chitinase. As a general rule, chitinases carrying such a C-terminal extension are localized in the vacuole and those lacking it are secreted out of the cell.…”

Isolation and partial characterization of a small chitin‐binding lectin from mistletoe (Viscum album)

“…In addition, VisalbCBA is However, dehydro-alanine, a typical [~-elimination product of cysteine was detected in all relevant cycles. The sequence data for hevein, nettle lectin and bean chitinase were taken from Broekaert et al [23], Beintema and Peumans [24] and Broglie et al [25], respectively. On the bottom line asterisks indicate identical amino acids at that position of the sequence whereas dots represent similar amino acids.…”

Identification of a 28,000 Dalton endochitinase in barley endosperm

“…In Figure 3 is shown the 54 N-terminal amino acids of protein C together with 40 residues of purified peptide obtained by cleavage with cyanogen bromide in 70% formic acid. The figure also includes the relevant parts of the predicted amino acid sequence of a bean leaf endochitinase derived from a cDNA clone by BROGLIE et al (4). Identical positioned residues (61 of 104) are boxed in order to visualize the expressed homology between the two proteins.…”

“…by chitinases which attach and destroy cell walls (18). Recently, a full-length cDNA sequence encoding an endochitinase from Phaseolus vulgaffs was published (4). The deduced amino acid Abbreviations: BASI = Badey ct-amylase/subtilisin inhibitor; dpm = disintegrations per minute; FPLC = Fast protein liquid chromatography; P-buffer = 50 mM-sodium phosphates, pH 6.0; PSI = Protein synthesis inhibitor; SDS-PAGE = Sodium dodecyl-sulphate polyacrylamide gel electrophoresis.…”