scholarly journals DNA sequences of a bovine gene and of two related pseudogenes for the proteolipid subunit of mitochondrial ATP synthase

1989 ◽  
Vol 260 (1) ◽  
pp. 249-258 ◽  
Author(s):  
M R Dyer ◽  
N J Gay ◽  
J E Walker
Keyword(s):  
Dna Sequence ◽  
Atp Synthase ◽  
Dna Sequences ◽  
Genomic Library ◽  
Bovine Genome ◽  
Mitochondrial Import ◽  
Bovine Gene ◽  
Mitochondrial Atp Synthase ◽  
Embryonic Origin ◽  
Dna Sequence Repeats

The dicyclohexylcarbodi-imide-reactive proteolipid is a membrane subunit of mitochondrial ATP synthase. In cows it is encoded by two different nuclear genes known as P1 and P2. These genes are expressed in a tissue-specific fashion which reflects the embryonic origin of the tissues. The proteins that they encode are synthesized in the cytosol, and are precursors of the proteolipid that have different mitochondrial import sequences of 61 and 68 amino acids respectively. By use of gene-specific probes derived from the bovine P2 cDNA, regions containing corresponding parts of the bovine P2 gene have been isolated from a bovine genomic library, and their DNA sequences and those of flanking and intervening regions have been determined. The sequence contains four exons, which represent the cDNA sequence, spread over 3.8 kb of the bovine genome. Two of the introns are in the DNA sequence coding for the mitochondrial import sequence, and a third intron is in a sequence encoding an extramembranous structure between the two putative transmembrane alpha-helical domains of the mature proteolipid. An Alu-type repetitive element was detected at the extreme 5′ end of the sequence. The bovine P1 and P2 genes for the dicyclohexylcarbodimide-reactive proteolipid of ATP synthase are members of a multiple gene family that also contains many pseudogenes. The bovine P1 gene has not been isolated, but two distinct P1 pseudogenes have been cloned and their DNA sequences have been determined. Both of them contain ‘in-phase’ stop codons and frame-shift mutations, and one of them bears the hallmarks of retroposition; it has no introns, it contains a poly(A) tract at its 3′ end and it is flanked by direct DNA sequence repeats. The second P1 pseudogene is very unusual. It appears to be derived from a partially processed transcript and contains an intervening DNA sequence of 861 bp that corresponds in position with an intron in the human P1 gene. This pseudogene also could have been introduced by retroposition since its sequence is flanked by short direct repeats. However, it does not contain a poly(A) tract at its 3′ end. An alternative, but less likely, explanation is that rather than being a retroposon, this sequence arose by duplication of an expressed gene at a time when it had only one intron.

scholarly journals Characterization of the expressed genes for subunit c of mitochondrial ATP synthase in sheep with ceroid lipofuscinosis

1993 ◽  
Vol 293 (1) ◽  
pp. 65-73 ◽  
Author(s):  
S M Medd ◽  
J E Walker ◽  
R D Jolly
Keyword(s):  
Atp Synthase ◽  
Mitochondrial Targeting ◽  
Mitochondrial Import ◽  
Fragment Analysis ◽  
Subunit C ◽  
Ceroid Lipofuscinosis ◽  
Mitochondrial Atp Synthase ◽  
C Subunit ◽  
Healthy Control

The human and bovine genomes each contain two expressed nuclear genes, called P1 and P2, for subunit c, a hydrophobic subunit of the membrane sector, Fo, of mitochondrial ATP synthase. Both P1 and P2 encode the same mature protein, but the associated mitochondrial import sequences are different. In sheep with the neurodegenerative disease ceroid lipofuscinosis, and also in humans with Batten's disease, unmodified subunit c accumulates in lysosome-derived organelles in a variety of tissues. However, the sequences of cDNAs for P1 and P2 from sheep with ceroid lipofuscinosis were identical to those in healthy control animals. Therefore, since there was no mutation in either of the mitochondrial import sequences of subunit c in the diseased animals, ceroid lipofuscinosis does not arise from changes in an import sequence causing mis-targeting of the c subunit to lysosomes. The levels of expression of P1 and P2 genes were approximately the same in diseased and healthy animals, and so the protein is unlikely to accumulate because of excessive transcription of either gene. Transcription of a spliced pseudogene related to P2 was detected in both a control animal and a sheep with ceroid lipofuscinosis. The transcripts encode amino acids 1-31 of the P2 mitochondrial targeting sequence. In the diseased animal, an arginine replaced a glutamine in the control sequence. However, restriction fragment analysis of genomic DNA from a further 12 sheep established that the sequence differences were not linked to ceroid lipofuscinosis.

scholarly journals Sequences of members of the human gene family for the c subunit of mitochondrial ATP synthase

1993 ◽  
Vol 293 (1) ◽  
pp. 51-64 ◽  
Author(s):  
M R Dyer ◽  
J E Walker
Keyword(s):  
Human Genome ◽  
Atp Synthase ◽  
Dna Sequences ◽  
Human Gene ◽  
Membrane Component ◽  
Subunit C ◽  
Coding Sequences ◽  
Mitochondrial Atp Synthase ◽  
C Subunit ◽  
Potential Promoter

Subunit c is an intrinsic membrane component of ATP synthase, and in mammals it is encoded by two expressed nuclear genes, P1 and P2. Both genes encode the same mature c subunit, but the mitochondrial import pre-sequences in the precursors of subunit c are different. The DNA sequences of the human P1 and P2 genes are described. They occupy about 3.0 and 10.9 kb respectively of the human genome, and both genes are split into five exons. The human genome also contains about 14 related spliced pseudogenes, and the sequence of one such pseudogene related to P2 is described. Sequences flanking the 5′ ends of the human P1 and P2 coding sequences each contain a CpG-rich island. Potential promoter elements (TATA and CCAAT boxes) are present in the 5′ sequences of the P1 gene, but not that of P2, although there is no direct experimental evidence to show the involvement of these sequences in transcription of the genes.

scholarly journals The sequence of the major protein stored in ovine ceroid lipofuscinosis is identical with that of the dicyclohexylcarbodiimide-reactive proteolipid of mitochondrial ATP synthase

1990 ◽  
Vol 268 (3) ◽  
pp. 751-758 ◽  
Author(s):  
I M Fearnley ◽  
J E Walker ◽  
R D Martinus ◽  
R D Jolly ◽  
K B Kirkland ◽  
...  
Keyword(s):  
Amino Acid ◽  
Atp Synthase ◽  
Direct Analysis ◽  
Proteolytic Processing ◽  
Major Protein ◽  
Lysosomal Storage ◽  
Post Translational Modification ◽  
Mitochondrial Import ◽  
Mitochondrial Atp Synthase ◽  
C Subunit

The ceroid lipofuscinoses are a group of neurodegenerative lysosomal storage diseases of children and animals that are recessively inherited. In diseased individuals fluorescent storage bodies accumulate in a wide variety of cells, including neurons. Previous studies of these bodies isolated from tissues of affected sheep confirmed that the storage occurs in lysosomes, and showed that the storage body is mostly made of a single protein with an apparent molecular mass of 3500 Da with an N-terminal amino acid sequence that is the same as residues 1-40 of the c-subunit (or dicyclohexylcarbodi-imide-reactive proteolipid) of mitochondrial ATP synthase. In the present work we have shown by direct analysis that the stored protein is identical in sequence with the entire c-subunit of mitochondrial ATP synthase, a very hydrophobic protein of 75 amino acid residues. As far as can be detected by the Edman degradation, the stored protein appears not to have been subject to any post-translational modification other than the correct removal of the mitochondrial import sequences that have been shown in other experiments to be present at the N-terminal of its two different precursors. No other protein accumulates in the storage bodies to any significant extent. Taken with studies of the cDNAs for the c-subunit in normal and diseased sheep, these results indicate that the material that is stored in lysosomes of diseased animals has probably entered mitochondria and has been subjected to the proteolytic processing that is associated with mitochondrial import. This implies that the defect that leads to the lysosomal accumulation concerns the degradative pathway of the c-subunit of ATP synthase. An alternative, but less likely, hypothesis is that for some unknown reason the precursors of subunit c are being directly mis-targeted to lysosomes, where they become processed to yield a protein identical with the protein that is normally found in the mitochondrial ATP synthase assembly, and which then accumulates.

DNA sequence mapping in interphase and metaphase chromosomes by fluorescence in situ hybridization

1992 ◽  
Vol 50 (1) ◽  
pp. 496-497
Author(s):  
Barbara Trask ◽  
Susan Allen ◽  
Anne Bergmann ◽  
Mari Christensen ◽  
Anne Fertitta ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Dna Sequence ◽  
Dna Sequences ◽  
Dual Band ◽  
Nick Translation ◽  
Metaphase Chromosomes ◽  
Band Pass ◽  
Texas Red ◽  
Fluorescent Spot

Using fluorescence in situ hybridization (FISH), the positions of DNA sequences can be discretely marked with a fluorescent spot. The efficiency of marking DNA sequences of the size cloned in cosmids is 90-95%, and the fluorescent spots produced after FISH are ≈0.3 μm in diameter. Sites of two sequences can be distinguished using two-color FISH. Different reporter molecules, such as biotin or digoxigenin, are incorporated into DNA sequence probes by nick translation. These reporter molecules are labeled after hybridization with different fluorochromes, e.g., FITC and Texas Red. The development of dual band pass filters (Chromatechnology) allows these fluorochromes to be photographed simultaneously without registration shift.

scholarly journals DNA thermodynamics shape chromosome organization and topology

2013 ◽  
Vol 41 (2) ◽  
pp. 548-553 ◽  
Author(s):  
Andrew A. Travers ◽  
Georgi Muskhelishvili
Keyword(s):  
Dna Sequence ◽  
Dna Sequences ◽  
Chromosome Organization ◽  
Topological Properties ◽  
Genetic Organization ◽  
And Topology ◽  
Dna Translocases

How much information is encoded in the DNA sequence of an organism? We argue that the informational, mechanical and topological properties of DNA are interdependent and act together to specify the primary characteristics of genetic organization and chromatin structures. Superhelicity generated in vivo, in part by the action of DNA translocases, can be transmitted to topologically sensitive regions encoded by less stable DNA sequences.

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