RESUMEN
A cDNA clone (AtPUMP) encoding a plant uncoupling mitochondrial protein was isolated from Arabidopsis thaliana. The cDNA contains an open reading frame of 921 nucleotides encoding 306 amino acids (predicted molecular weight 32,708). The predicted polypeptide is 81% identical and 89% similar to the potato UCP-like protein, and includes an energy transfer protein motif common to mitochondrial transporters. The AtPUMP gene exists as a single copy in the Arabidopsis genome. The corresponding transcript was expressed in all tissues and was strongly induced by cold treatment. We suggest that the putative AtPUMP protein may play a role in heat-requiring physiological events in Arabidopsis.
Asunto(s)
Arabidopsis/genética , Proteínas Portadoras/genética , Proteínas de la Membrana/genética , Mitocondrias , Proteínas de Plantas/genética , Desacopladores , Secuencia de Aminoácidos , Secuencia de Bases , Clonación Molecular , Frío , ADN Complementario/genética , Dosificación de Gen , Regulación de la Expresión Génica de las Plantas , Genes de Plantas , Canales Iónicos , Proteínas Mitocondriales , Datos de Secuencia Molecular , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido , Distribución Tisular , Proteína Desacopladora 1RESUMEN
Coronatine is a phytotoxin produced by some plant-pathogenic bacteria. It has been shown that coronatine mimics the action of methyl jasmonate (MeJA) in plants. MeJA is a plant-signaling molecule involved in stress responses such as wounding and pathogen attack. In Arabidopsis thaliana, MeJA is essential for pollen grain development. The coi1 (for coronatine-insensitive) mutant of Arabidopsis, which is insensitive to coronatine and MeJA, produces sterile male flowers and shows an altered response to wounding. When the differential display technique was used, a message that was rapidly induced by coronatine in wild-type plants but not in coi1 was identified and the corresponding cDNA was cloned. The coronatine-induced gene ATHCOR1 (for A. thaliana coronatine-induced) is expressed in seedlings, mature leaves, flowers, and siliques but was not detected in roots. The expression of this gene was dramatically reduced in coi1 plants, indicating that COI1 affects its expression. ATHCOR1 was rapidly induced by MeJA and wounding in wild-type plants. The sequence of ATHCOR1 shows no strong homology to known proteins. However, the predicted polypeptide contains a conserved amino acid sequence present in several bacterial, animal, and plant hydrolases and includes a potential ATP/GTP-binding-site motif (P-loop).
Asunto(s)
Acetatos/farmacología , Aminoácidos/farmacología , Proteínas de Arabidopsis , Arabidopsis/genética , Ciclopentanos/farmacología , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Genes de Plantas , Proteínas de Choque Térmico/genética , Indenos/farmacología , Mutación , Proteínas de Plantas/genética , Secuencia de Aminoácidos , Arabidopsis/efectos de los fármacos , Arabidopsis/fisiología , Secuencia de Bases , Clonación Molecular , Resistencia a Medicamentos/genética , Proteínas de Choque Térmico/biosíntesis , Datos de Secuencia Molecular , Oxilipinas , Proteínas de Plantas/biosíntesisRESUMEN
A full-length cDNA clone encoding a sulfur-rich Coix prolamin was isolated using a cDNA library constructed from polysomal mRNA prepared from immature Coix endosperm. The deduced amino acid sequence of the cDNA clone predicted a polypeptide of 194 residues, which shared 64% homology with the 17 kDa beta-zein. The mature protein contains the familiar composition of the prolamins and an unusually high content of the sulfur-containing amino acids methionine (11.6%) and cysteine (5.2%). In vitro transcription followed by in vitro translation of the coding region of the pBCX17.9S clone gave rise to a polypeptide with an apparent molecular weight corresponding to the C4 alpha-coixin. Hydropathy analysis showed that C4 alpha-coixin is slightly more hydrophobic than beta-zein.
Asunto(s)
Proteínas de Plantas/genética , Poaceae/genética , Secuencia de Aminoácidos , Secuencia de Bases , Clonación Molecular , Datos de Secuencia Molecular , Proteínas de Plantas/química , Homología de Secuencia de Ácido Nucleico , Zeína/químicaRESUMEN
Zeins from Zea mays L cv. Maya and coixins from Coix lacryma-jobi L. cv. Adlay were fractionated to obtain alpha-, beta-, and gamma-zein and alpha-, beta-, and gamma-coixin. The alpha-coixins were composed of 4 polypeptide classes of 27 kDa (C1), 25 kDa (C2), 17 kDa (C4) and 15 kDa (C5) with solubility properties very similar to those of the 22 kDa and 19 kDa alpha-zeins. Like the alpha-zeins, the C1 and C2 alpha-coixins corresponded to 80% of total Coix prolamins. The fraction corresponding to gamma-coixin contained only one protein band of 22 kDa (C3). This coixin fraction has solubility properties similar to those of gamma-zein and represents 15% of the total coixin. The beta-zein fraction was composed of a major 17 kDa protein band, while the beta-coixin fraction consisted of a mixture of alpha- and gamma-coixins. Polyclonal antibodies raised against C1 recognized C1 and C2 and cross-reacted strongly with the 22 kDa alpha-zein, as did C4 and C5 antisera. The antiserum against gamma-coixin showed strong cross-reaction with gamma-zein. The homology between coixins and zeins was further investigated by using Southern hybridization analyses. The genomic DNA of maize and Coix were digested with several restriction enzymes and probed with cDNA clones representing 19 and 22 kDa alpha-zeins as well as the 28 and 16 kDa gamma-zeins. The Coix genome showed complex cross-hybridization sequences with the 22 kDa alpha-zein cDNA, while no cross-hybridization was observed with the 19 kDa cDNA clone.(ABSTRACT TRUNCATED AT 250 WORDS)