Post-transcriptional regulation of a salt-inducible alfalfa gene encoding a putative chimeric proline-rich cell wall protein.
A cDNA previously shown to identify a salt-inducible root-specific transcript in Medicago sativa was used to screen an alfalfa library for the corresponding genomic sequence. One positive clone was recovered. The nucleotide sequence of a subclone contained a 329 bp 5' region upstream of the first ATG codon, a 1143 bp coding segment, and a 447 bp 3'-untranslated region interrupted by a single 475 bp intron. Translation of the coding segment, which was designated MsPRP2, suggested it encodes a chimeric 40,569 Da cell wall protein with an amino-terminal signal sequence, a repetitive proline-rich sequence, and a cysteine-rich carboxyl-terminal sequence homologous to nonspecific lipid transfer proteins. The 3'-untranslated region of MsPRP2 contained a sequence similar to one found to destabilize mRNAs transcribed from the elicitor-regulated proline-rich protein gene PvPRP1. Transcription run-on experiments using nuclei from salt-sensitive and salt-tolerant alfalfa callus suggested that the accumulation of MsPRP2 transcripts in salt-tolerant alfalfa cells grown in the presence of salt is due primarily to increased mRNA stability. The MsPRP2 gene thus may be a useful model for studying post-transcriptional salt-regulated expression of cell wall proteins.
Deutch
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Department of Biochemistry, University of Nevada, Reno 89557.
Winicov
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D000595:Amino Acid Sequence; D001483:Base Sequence; D002473:Cell Wall / Q000737:chemistry*; D003001:Cloning, Molecular; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D017343:Genes, Plant / Q000235:genetics; D000455:Medicago sativa / Q000235:genetics*; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000378:metabolism*; D018749:RNA, Plant / Q000096:biosynthesis / Q000378:metabolism*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D012965:Sodium Chloride / Q000494:pharmacology; D014158:Transcription, Genetic
C092522:MsPRP2 protein, Medicago sativa; D010940:Plant Proteins; D012333:RNA, Messenger; D018749:RNA, Plant; D012965:Sodium Chloride