Biochemical Studies on the <i>Iojap</i> Mutant of Maize

Siemenroth, Anke; Börner, Thomas; Metzger, Ulrich

doi:10.1104/pp.65.6.1108

Cited by 20 publications

(18 citation statements)

References 12 publications

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“…This study shows that the ribosome loss does not result from photodamage, but is one of the characteristics of the plastids affected by/jl. Also, this result is consistent with the previous report that Rubisco holoenzyme and ATPase are not detectable (Siemenroth et al 1980). Neither the plastid-encoded cytochrome f nor the nucleus-encoded Rieske protein were accumulated in the defective plastids.…”

Section: Discussionsupporting

confidence: 94%

“…10e). The reduction in the level of the enzyme could be an explanation for the previous report that the activity of the enzyme was decreased 60% in the white seedlings (Siemenroth et al 1980). The levels of the proteins in yellow seedlings were slightly higher than in white seedlings.…”

Section: Almost Identical Patterns Of Transcripts Between Ijlmentioning

confidence: 78%

“…Previous biochemical and molecular studies on ijl have been with seedlings grown under greenhouse conditions (Walbot and Coe 1979;Siemenroth et al 1980). Under such conditions, other albino mutants that have been known to be blocked in the biosynthetic pathway of carotenoids tend to lose plastid ribosomes and internal membranes by photodamage (Bachmann et al 1968;Reiss et al 1983;Mayfield et al 1986).…”

Section: Resultsmentioning

confidence: 99%

“…This hypothesis has been proposed based on the observation that rRNAs and plastid proteins were not detectable (Walbot and Coe 1979;Siemenroth et al 1980). However, we found that the 0"1 seedlings and maternal-exception seedlings not only contain transcripts of plastid genes but also show almost identical patterns of plastid transcripts.…”

Section: Discussionmentioning

confidence: 96%

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Aberrations in plastid transcripts and deficiency of plastid DNA in striped and albino mutants in maize

Han

Patrie

Polacco

et al. 1993

Planta

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Abstract.To better understand the regulatory roles of nuclear genes in chloroplast genomic expression during leaf development in maize (Zea mays L.), we studied a striped mutant, iil (iojap 1), two albino mutants, wl (white 1) and w2 (white 2), and their double mutants with l (luteus). Homozygous ijl plants as a female parent produce albino seedlings, called maternal exceptions, among their progeny, even when the nuclear genotype of the male parent is normal (4-/4-). In contrast to albinos that are blocked in the biosynthetic pathway of carotenoids, wl and w2 seedlings fail to accumulate chlorophyll and carotenoids up to the normal level even under dim light conditions. In ijl-affected plastids, the plastid-encoded proteins and nuclear-encoded proteins that are associated with thylakoid membranes were not detecable. However, the 33-kDa protein of the oxygen-evolving complex and ferredoxin: NADP oxidoreductase, which are localized extrinsically, were accumulated even though the level of the proteins was decreased. Both ijl and wl albino seedlings contain a normal level of plastid DNA. However, both show similar aberrant patterns among the transcripts of all the plastid genes examined (psbB, psbH, petB, petD, atpA, psaB, psbA, and rbcL). Not only were additional transcripts detected but some of the normal transcripts were not detectable or were barely detectable by Northern hybridization. These facts indicate that the transcripts of ijl-and wl-affected plastids may have altered synthesis, processing or stability. Therefore, the block in expression of the plastid genome by the nuclear mutants ijI and wl may be due to alterations in the transcriptional or post-transcriptional processes. The fact that ijl and maternal-exception progeny show almost * Present address: Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, USA ** Present address: Department of Biological Sciences, State University of New York, Binghamton, New York, USA Abbreviations: FNR = ferredoxin: NADP oxidoreductase; OEC-33=33-kDa protein of the oxygen-evolving complex; Rubisco = ribulose-l,5-bisphopsphate carboxylase oxygenase Correspondence to: E.H. Coe identical patterns of transcripts indicates that the effects of ijl on plastid gene expression persist in the subsequent generation even after the nuclear gene, ljl, restores the normal function. In contrast to ijl and wl, the levels of all plastid transcripts in w2 seedlings, whether l or 4-, are uniformly reduced. Compared to normal sibling seedlings, the patterns of the RNA species are relatively unaltered. Relative to the level of a nuclear rDNA, the plastid DNA content of w2 is decreased 20-fold. Therefore, the limited expression of the w2-affected plastids may be due to failure to maintain the copy number of plastid genomes. Thus, albinisms of these mutants result from limiting of expression of plastids due to alteration of transcripts on the one hand, or to lowered DNA content on the other.

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Section: Discussionsupporting

confidence: 94%

Section: Almost Identical Patterns Of Transcripts Between Ijlmentioning

confidence: 78%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 96%

See 2 more Smart Citations

Aberrations in plastid transcripts and deficiency of plastid DNA in striped and albino mutants in maize

Han

Patrie

Polacco

et al. 1993

Planta

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“…Therefore, 0 :4 Chloroplast biogenesis requires cytoplasmically synthesized proteins as well as those of chloroplast origin. Mutant strains of plants (12,23,26) and algae (13,16) deficient in chloroplast ribosomes have proven useful in the study of the interdependence of the chloroplast and nuclear genomes. Among these, the chloroplast ribosome-deficient mutant of Chlamydomonas reinhardtii, ac20crl, has been characterized in some detail (e.g.…”

mentioning

confidence: 99%

Posttranscriptional Regulation of Ribulose 1,5-bisphosphate Carboxylase Small Subunit Accumulation in Chlamydomonas reinhardtii

Mishkind

Schmidt²

1983

Plant Physiol.

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The coordinated synthesis of the subunits of ribulose 1,5-bisphosphate carboxylase was examined by analysis ofthe ch}oroplast ribosome-deficdeat mutant of Chiamydomonas re ardtii, ac2Ocrl. The absence of the chloroplast-synthesized large subunit of this enzyme from cells of this strain is a direct consequence of the lack of chloroplast nbosomes. In contrast, the absence of the cytoplasmicafly-synthesized small subunit of ribuose 1,5-bisphosphate carboxylase from this mutant is not understood. To discern the cause of this absence, we have compared results of in vivo radioactive labeling experiments with those of ceDl-free translations of RNA from ac20crl. Protein products from these experiments were identified by oneand two-dimensional electrophoretic analyses. Neither subunit, revealed either as a stained band or by fluorography ofproteins radioactively labeled in vim for 2 hours, was detected in ac2Ocrl. Cell-free translation of polyadenylated RNA obtained from ac20crl, however, revealed wild-type levels of mRNA for the precursor to the small subunit. This messenger was found to be associated with subribosomal RNP and polysomes. We conclude that the absence of the small subunit of ribulose 1,5-bisphosphate carboxylase from ac2Ocrl is the result of a translational or posttranslational event.in ac20crl at wild-type levels during heterotrophic growth (24), free pools of the cytoplasmically synthesized S of RuBPCase are not detected in these cells (9). Thus, there appears to be a specific interaction between the chloroplast and cytoplasm that serves to regulate the accumulation of S. The experiments in this paper were designed to identify the site(s) at which control of S synthesis is exerted. We demonstrate by in vivo labeling experiments analyzed by two-dimensional pH gradient gel electrophoresis that pools ofpS as well as pools of S itself are not present in detectable levels in ac2Ocrl. We also find that heterotrophically grown cells of ac20crl contain wild-type levels of mRNA for this subunit and that some of this messenger is present on polysomes. Therefore, 0

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Use of nuclear mutants in the analysis of chloroplast development

1987

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Although a wide range of mutations in the nuclear genome also affect chloroplast biogenesis, their pleiotropic nature often limits their use in studying nuclear genes that regulate or facilitate chloroplast development. However, many mutations that cause a high-chlorophyll-fluorescent (hcf) phenotype exhibit limited pleiotrophy, causing the loss of functionally related sets of chloroplast polypeptides. Several hcf mutations are described that result in the loss of one specific protein complex from the thylakoid membrane. Chloroplast and cytosolic mRNAs coding for component polypeptides of the missing complex are unaffected in the mutants, suggesting that each mutation disrupts some process in the synthesis and assembly of the missing complex. Another hcf mutation causes both the loss of three protein complexes and grossly abnormal thylakoid membrane structures. The primary effect of this mutation might be in the assembly of thylakoid membranes or in the stable accumulation of the three protein complexes. Two other hcf mutations are more pleiotropic. Hcf*-38 causes a quantitative reduction of many chloroplast proteins and a reduction of some chloroplast RNAs, including several splicing intermediates. Hcf*-7 causes a major reduction of all chloroplast-encoded proteins examined. The range of pleiotropic effects of hcf mutations indicates that the mutations identify nuclear genes whose products are involved in a number of different steps in chloroplast development. Because some of the mutations described have been generated by transposon insertions, they can be cloned using the transposon to identify the mutant allele.

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Biochemical Studies on the Iojap Mutant of Maize

Cited by 20 publications

References 12 publications

Aberrations in plastid transcripts and deficiency of plastid DNA in striped and albino mutants in maize

Aberrations in plastid transcripts and deficiency of plastid DNA in striped and albino mutants in maize

Posttranscriptional Regulation of Ribulose 1,5-bisphosphate Carboxylase Small Subunit Accumulation in Chlamydomonas reinhardtii

Use of nuclear mutants in the analysis of chloroplast development

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