Expression of a novel-type small proline-rich protein gene of alfalfa is induced by 2,4-dichlorophenoxiacetic acid in dedifferentiated callus cells.
Differential screening of a cDNA library of 2,4-dichlorophenoxiacetic acid (2,4-D)-treated alfalfa (Medicago sativa) callus tissues resulted in the isolation of a 571 bp cDNA clone (MsPRP5) encoding for a proline-rich protein (84 amino acids) with a specific repeat unit of TPVLPPRK/RGRPPPVPP. In addition, a characteristic amino acid block (PPVYK) previously found in other proline-rich proteins also occurs in the C-terminal region of MsPRP5. At the N-terminal, a signal peptide similar to leader sequences of extracellular proteins can be predicted. According to the northern analysis, the corresponding gene is not expressed or is weakly expressed in differentiated vegetative organs and somatic embryos. However the accumulation of MsPRP5 mRNA is auxin concentration-dependent in dedifferentiated callus tissue. An increase in the amount of steady-state mRNA was detected already 20 min after auxin shock (100 microM 2,4-D). Maximum expression was observed at 24-48 h in the presence of 2,4-D. Elevated expression was also found in cells recovering after heat shock and wounding stress. In synchronized alfalfa cells, the transcript level of MsPRP5 gene fluctuated during cell cycle progression with peaks in G1/S phase cells. Considering the structural features and expression properties of MsPRP5, this clone may represents a new type of proline-rich protein gene which responds to hormonal shock and some other stresses as well.
Györgyey
J
J
Institute of Plant Biology, Hungarian Academy of Sciences, Szeged, Hungary.
Németh
K
K
Magyar
Z
Z
Kelemen
Z
Z
Alliotte
T
T
Inzé
D
D
Dudits
D
D
D015084:2,4-Dichlorophenoxyacetic Acid / Q000494:pharmacology*; D000595:Amino Acid Sequence; D001483:Base Sequence; D002453:Cell Cycle / Q000235:genetics; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured / Q000187:drug effects; D018076:DNA, Complementary / Q000235:genetics; D018628:Gene Dosage; D018506:Gene Expression Regulation, Plant; D015723:Gene Library; D006360:Heat-Shock Proteins / Q000235:genetics*; D007210:Indoleacetic Acids / Q000494:pharmacology*; D000455:Medicago sativa / Q000166:cytology / Q000187:drug effects / Q000235:genetics*; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D010940:Plant Proteins; D011392:Proline; D011487:Protein Conformation; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D006360:Heat-Shock Proteins; D007210:Indoleacetic Acids; C107437:PRP5 protein, Medicago sativa; D010940:Plant Proteins; D015084:2,4-Dichlorophenoxyacetic Acid; D011392:Proline