Isolation and characterization of a cDNA clone encoding a putative white spruce glycine-rich RNA binding protein

A presumably full-length cDNA encoding a putative glycine-rich RNA binding protein was isolated from a lambda ZAP cDNA library prepared from mRNAs ext racted from needles of 2 year old white spruce seedlings, which had been ei ther wounded or jasmonate-treated. The cDNA, designated PgRNP (Picea glauca RNP protein), presents a 468 bp open reading frame encoding a 155 amino ac id protein. This polypeptide possesses an RNA binding domain (RNP-CS) and a glycine-rich domain. Comparative alignment reveals extensive homologies to glycine-rich RNA binding proteins containing an RNP-CS found in other angi osperm species. Genomic hybridization experiments suggest that the PgRNP ge ne is part of a small multigene family with at least four members. RNA blot analysis revealed that the PgRNP transcript is expressed in all tissues fr om non-stressed plants. Constitutive mRNA level was found in needle tissue from control as well as methyl-jasmonate treated plants. Wounding had no cl ear induction effect. Jasmonic acid treatment and systemic wound response h ad a positive effect on transcript accumulation. Transcript accumulation wa s slightly induced by cold in needles, and repressed by drought stress in b oth needle and root tissues of 2 year old plants. Finally, the level of PgR NP accumulation was induced by wounding and repressed in 2 week old dark-gr own seedlings upon jasmonate treatments. (C) 1999 Elsevier Science B.V. All rights reserved.