Organization of the mitochondrial ribosomal RNA genes of maize

Stern, David B.; Dyer, Tristan A.; Lonsdale, David

doi:10.1093/nar/10.11.3333

Cited by 64 publications

(16 citation statements)

References 35 publications

(3 reference statements)

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“…Such introns are absent from the rRNA genes of mammalian and most other animal mtDNA, but have been found in chloroplast rRNAs of Chlamydomonas (14) and Zea mays (15) and in the mitochondrial genomes of N. Crassa (12) and S. cerevisiae (16 Note Added in Proof. Since our work was completed, similar conclusions regarding the organization ofthe ribosomal genes ofmaize mtDNA have been published (20). We are grateful to Cheryl Daum Heiner and Patricia White for technical assistance in part of this work and to Joyce Heckman for helpful discussions.…”

supporting

confidence: 58%

Mapping the mitochondrial DNA of Zea mays : Ribosomal gene localization

Iams

1982

Proc. Natl. Acad. Sci. U.S.A.

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We have located the 18S and 26S ribosomal genes on a 32.2-kilobase pair (kb) restriction map of Zea mays mitochondrial DNA. In a BamHI restriction digest of mitochondrial DNA, band 4 carries all of the 26S gene whereas band 2 carries the 18S gene sequence. We have cloned and mapped bands 2 and 4 and show that they are contiguous in the genome. The 26S sequence is at one end of the 13.7-kb fragment 4, immediately adjacent to thejunction with fragment 2. The 18S sequence is located at the far end of the 17.5-kb fragment 2, about 15 kb away from the 26S gene. A second region of 18S sequence homology is found on band 40. This region contains sequences that cross-hybridize with those in band 2. The nature of this apparent sequence repetition is unclear.The mitochondria of Zea mays and other higher plants have a genome size some 20-30 times as large as that of animals and some 5 or more times the size of yeast. In Zea mays mtDNA, this seems not to be a result of significant repetitive sequences (1). Determination of the size of this genome by summation of fragments produced by restriction enzymes is complicated by the large number of identical or similar-sized bands, and estimates of genome size from the literature vary from as small as 175 kilobase pairs (kb) (2) to as large as 600 kb (1). Our own estimates indicate a size of about 400 kb (unpublished data).Little is yet known about the physical organization of this large genome, although evidence from electron microscopy suggests that genes may be distributed among several circular molecules (2). If true, this will be the first instance of multiple molecules in organelle genomes.In vivo protein synthesis experiments indicate that maize mtDNA codes for about 18 polypeptides (3). The gene for a part of cytochrome oxidase has been mapped and sequenced (4). Ribosomal RNAs have been identified for maize mtDNA and located on restriction patterns (5, 6).To facilitate the mapping ofthe 18S and 26S genes, we cloned restriction enzyme-digested mtDNA in the plasmid pBR322. These clones were restriction mapped and used as probes to determine the orientation and copy number ofthese two genes. Only one gene codes for the 26S rRNA, and this is located approximately 15 kb from the 18S ribosomal sequence. However, the 18S sequence seems to be partially duplicated in other parts of the genome.MATERIALS AND METHODS Isolation of Mitochondria, mtDNA, mtRNA, and Escherichia coli rRNA. Mitochondria were isolated and mtDNA was extracted from sterile, etiolated seedlings of strain FRB 73 (Illinois Foundation Seeds, Inc.) by methods adapted from Levings and Pring (2). Mitochondria were prepared for RNA extraction in much the same way as for DNA up to the point of DNAse digestion. After this, RNA was extracted essentially as described by Pring (7). E. coli rRNA was extracted from frozen cells. A 25-g pellet was suspended in 15 ml ofbuffer (50 mM Tris, pH 7.2/10 mM MgCl2/30 mM NH4Cl/1 mM dithiothreitol), digested with DNase 1 (10 ug/ml), and disrupted by three passes through a French ...

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confidence: 58%

Mapping the mitochondrial DNA of Zea mays : Ribosomal gene localization

Iams

1982

Proc. Natl. Acad. Sci. U.S.A.

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“…rm26 (Stern et al, 1982), rmZ8 and rrn5 (Chao et al, 1984), nadl (Chapdelaine and Bonen, 1991), atpA (Braun and Levings, 1985), atp6 (Dewey et al, 1985), atp9 (Young et al, 1986), coxI (Bonen et al, 1987), coxII (Fox and Leaver, 1981), and cob (Boer et al, 1985). To identify a species-specific RFLP in ctDNA, oligonucleotide-labeled probes were prepared from gel-purified inserts of a recombinant clone carrying a 27-kb Sal1 fragment from tomato ctDNA (Bonnema et al, 1991).…”

Section: N a Extraction And Southern Analysismentioning

confidence: 99%

Molecular and Ultrastructural Analysis of a Nonchromosomal Variegated Mutant (Tomato Mitochondrial Mutants That Cause Abnormal Leaf Development)

et al. 1995

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Mutants were recovered i n a population of cybrids formed following protoplast fusion between tomato (Lycopersicon esculentum Mill.) cv UC82 and Lycopersicon pennellii Corr. The cybrids were identified as individuals with recombinant cytoplasmic genomes but only tomato nuclear genomes. The mutants were identified based on two features, a variegated sectoring of light and dark green regions on their leaves, stems, and fruit, and reduced growth in the field. The mutants produced 50% of the shoot fresh weight and 20% of the fruit fresh weight of the parenta1 type, UC82. The variegated sectoring was maternally inherited. The chloroplast genome in the mutants was indistinguishable from the chloroplast genome in UC82, when distribution of restriction endonuclease sites was used as an assay. The mitochondrial genome i n the mutants, however, was recombinant, containing genes from UC82 and L. pennellii. Light microscopic analysis of the leaves of the mutants demonstrated an absence of the palisade layer i n the variegated sectors. Electron microscopic analysis of these same regions demonstrated an absence of normal inner membranes in the mitochondria of these cells.

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“…Even the smallest higher plant mtDNAs are surprisingly complex compared to animal (15 kb; (23) or Saccharomyces (75 kb; (8)) mtDNAs, or even to the chloroplast genome (128-146 kb; (11)). Despite the large amount of available DNA, current evidence suggests that maize mitochondria synthesize only a few more proteins than yeast mitochondria (13), and the genome appears to encode a single copy of the ribosomal RNA genes (9,25). The unexpectedly large size may be associated with rearrangement phenomena such as those involved in cytoplasmic male sterility (14) and/or the presence of large blocks of chloroplast DNA stably integrated into the mtDNA (17,26).…”

Section: Introductionmentioning

confidence: 99%

Sequence of histidyl tRNA, present as a chloroplast insert in mtDNA ofZea mays

Iams¹,

Heckman

1985

Plant Mol Biol

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Unfractionated tRNA, isolated from maize mitochondria, has been specifically labeled at the -CCA end and used to recover a tRNA gene-bearing fragment from a clone bank of maize mitochondrial DNA. This gene has been mapped, sequenced and found to carry the anticodon for histidine. The sequence of the gene and that of bases in its near vicinity are identical to maize chloroplast tRNA(His), although sequences more distant on the fragment are not homologous with cpDNA. The junction of the cpDNA insert has been sequenced.

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Organization of the mitochondrial ribosomal RNA genes of maize

Cited by 64 publications

References 35 publications

Mapping the mitochondrial DNA of Zea mays : Ribosomal gene localization

Mapping the mitochondrial DNA of Zea mays : Ribosomal gene localization

Molecular and Ultrastructural Analysis of a Nonchromosomal Variegated Mutant (Tomato Mitochondrial Mutants That Cause Abnormal Leaf Development)

Sequence of histidyl tRNA, present as a chloroplast insert in mtDNA ofZea mays

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