On the Role of Stored mRNA in Protein Synthesis in Embryonic Axes of Germinating <i>Vigna unguiculata</i> Seeds

Suzuki, Yoshiharu; Minamikawa, Takao

doi:10.1104/pp.79.2.327

Cited by 21 publications

(10 citation statements)

References 23 publications

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“…The experiments undertaken with CHI and ACT-D suggest that the salt-induced OAT activity may proceed via NaCl activation of the translation of pte-existing mRNAs corresponding to OAT. Such stored tnRNAs have previously been detected in many seeds (Payne 1976;Sitnon 1984;Suzuki & Minamikawa 1985). Moreover, long-lived .stored mRNAs are actually translated during the early germination of radish seeds (Aspart et al 1984).…”

Section: Discussionmentioning

confidence: 92%

Contribution of ornithine aminotransferase to proline accumulation in NaCl‐treated radish cotyledons

Hervieu

Dily

Huault

et al. 1995

Plant Cell & Environment

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Light‐grown cotyledons of radish (Raphanus sativus L. cv National) subjected to increasing NaCI concentrations displayed a dose‐dependent accumulation of proline at the beginning of their differentiation. Neither erythromycin nor DCMU significantly affected the salt‐induced proline accumulation, which suggests that plastids may not be involved in proline synthesis. Gabaculine has been shown previously to be a powerful and irreversible inhibitor of ornithine aminotransferase [Hervieu et al. (1993) Phyto‐chemistry 34, 231–234]. This inhibitor applied in vivo at a very low concentration (1 mmol m−3) reduced considerably the salt‐induced proline accumulation of radish cotyledons. These results indicate that the ornithine pathway contributes, via an increase of ornithine aminotransferase activity, to proline synthesis, as well as the glutamate pathway, in salt‐treated cotyledons. The use of transcription and translation inhibitors revealed that the salt‐induced increase in ornithine aminotransferase activity may proceed via an activation of the translation of preformed mRNAs. The pre‐existing ornithine aminotransferase mRNAs in radish seeds may be an important adaptation to NaCI, leading to proline accumulation at the beginning of seedling growth.

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Section: Discussionmentioning

confidence: 92%

Contribution of ornithine aminotransferase to proline accumulation in NaCl‐treated radish cotyledons

Hervieu

Dily

Huault

et al. 1995

Plant Cell & Environment

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“…RNA fraction was prepared from day-9 germinated seeds as described previously (Suzuki and Minamikawa, 1985). Polyadenylated RNA was obtained from the total RNA using Oligotex dT-30 Super (Daiichi Pure Chemical).…”

Section: Construction and Screening Of Cdna Libraries A Totalmentioning

confidence: 99%

Identification and Characterization of a Rice Cysteine Endopeptidase that Digests Glutelin

Kato

Minamikawa

1996

European Journal of Biochemistry

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Little or no endopeptidase activity was detected in extracts from storage organs of dark-grown rice seeds until day 6 or post-imbibition, and the activity expressed per seed increased notably after day 9, reached a maximum on day 18, then decreased. Two major endopeptidases, REP-1 and REP-2, were present in the 40-75% saturated ammonium sulfate fi-action from day-9 germinated seeds, and could be separated by hydrophobic column chromatography. REP-I was further purified to a single polypeptide of 36 kDa. REP-1 digested in vitro both the acidic and basic subunits of rice glutelin, the major seed storage protein of rice. Determination of the N-terminal amino acid sequence and experiments with protease inhibitors indicated that REP-1 is a cysteine endopeptidase. The nucleotide sequence of a full-length REP-I cDNA was determined by a combination of screening of cDNA libraries from rice seeds and the 5' rapid amplification of cDNA ends technique.

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“…Construction and Screening of cDNA Libraries-Total RNA was prepared from day 3 cotyledons as described previously (24). Poly(A) ϩ RNA was obtained from total RNA using Oligotex(dT) 30 super (Daiichi Pure Chemical).…”

Section: Sds-page Andmentioning

confidence: 99%

Identification of a Membrane-associated Cysteine Protease with Possible Dual Roles in the Endoplasmic Reticulum and Protein Storage Vacuole

Okamoto

Toyooka²,

Minamikawa

2001

Journal of Biological Chemistry

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SH-EP is a vacuolar cysteine proteinase from germinated seeds of Vigna mungo. The enzyme has a C-terminal propeptide of 1 kDa that contains an endoplasmic reticulum (ER) retention signal, KDEL. The KDEL-tail has been suggested to function to store SH-EP as a transient zymogen in the lumen of the ER, and the C-terminal propeptide was thought to be removed within the ER or immediately after exit from the ER. In the present study, a protease that may be involved in the post-translational processing of the C-terminal propeptide of SH-EP was isolated from the microsomes of cotyledons of V. muno seedlings. cDNA sequence for the protease indicated that the enzyme is a member of the papain superfamily. Immunocytochemistry and subcellular fractionation of cotyledon cells suggested that the protease was localized in both the ER and protein storage vacuoles as enzymatically active mature form. In addition, protein fractionations of the cotyledonary microsome and Sf9 cells expressing the recombinant protease indicated that the enzyme associates with the microsomal membrane on the luminal side. The protease was named membrane-associated cysteine protease, MCP. The possibility that a papain-type enzyme, MCP, exists as mature enzyme in both ER and protein storage vacuoles will be discussed. The endoplasmic reticulum (ER)1 is the port of entry of proteins into the endomembrane system. In this organelle, there are a number of soluble proteins, membrane proteins, and molecular chaperones which are involved in folding, glycosylation, assembly, and maturation of nascent proteins (1-3). The soluble proteins localized in the lumen of the ER have a retention signal, KDEL or HDEL, at the C terminus (4 -6), and this signal is known to be recognized by the K(H)DEL receptor on the Golgi complex, which mediates retrieving K(H)DELtailed proteins to the ER. The molecular mechanisms of the ER retention of soluble proteins are conserved through animal, plant, and yeast cells (7-9).In several kinds of plants, unique papain-type proteinases possessing a C-terminal KDEL sequence have been identified (10 -16). One such KDEL-tailed cysteine protease, designated SH-EP, was first isolated from cotyledons of germinated Vigna mungo seeds as the enzyme responsible for degradation of storage proteins accumulated in protein storage vacuoles (PSV) of cotyledon cells (10, 17). SH-EP is synthesized on membranebound ribosomes as a 43-kDa precursor through co-translational cleavage of the signal peptide, and the precursor is processed to the 33-kDa mature enzyme via 39-and 36-kDa intermediates during or after transport to the vacuoles (18,19).The function of the KDEL-tail on a cysteine protease whose final destination is the PSV has been an interesting question. Based on analysis of the heterologous expression of SH-EP and a KDEL deletion mutant of SH-EP in insect Sf9 cells and subcellular fractionation of cotyledon cells, it was proposed that the KDEL-tail of SH-EP functions to store the enzyme as a transient zymogen in the ER, and that the conversion of the ...

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On the Role of Stored mRNA in Protein Synthesis in Embryonic Axes of Germinating Vigna unguiculata Seeds

Cited by 21 publications

References 23 publications

Contribution of ornithine aminotransferase to proline accumulation in NaCl‐treated radish cotyledons

Contribution of ornithine aminotransferase to proline accumulation in NaCl‐treated radish cotyledons

Identification and Characterization of a Rice Cysteine Endopeptidase that Digests Glutelin

Identification of a Membrane-associated Cysteine Protease with Possible Dual Roles in the Endoplasmic Reticulum and Protein Storage Vacuole

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