cDNA cloning and sequencing for the import precursor of coupling factor 6 in H(+)-ATP synthase from rat liver mitochondria

Genome-wide identification of female-enriched genes in zebrafish

Characteristic differences in morphology, physiology, and behavior between a male and female are correlated to the differential selection of sex-dependent transcriptomes. By using a cDNA array carrying approximately 9,000 zebrafish unique genes, we identified a group of genes whose expression are enriched in the female fish. A subset of these genes have been confirmed and further grouped as egg-enriched genes, as both somatic- and egg-enriched genes or as somatic-enriched genes by means of RNA gel blot hybridization. Most importantly, a significant proportion of these genes are either functionally unknown or are novel genes. Thus, future studies of this group of genes will help us greatly to understand more about sex-determination and sex-related physiology and behavior. In addition, comparison of zebrafish female-enriched genes with that in Drosophila, we found that only germline genes are shared between vertebrate and invertebrate, suggesting that the process of oogenesis is highly conserved during the evolution.

Synchronized transcriptional gene expression of H+-ATP synthase subunits in different tissues of Fischer 344 rats of different ages

Little is known about the relationship between the stoichiometry of polypeptides of multisubunit enzyme complexes and the absolute amount of each transcript of the complexes in mammalian tissues. Here we showed that the absolute amounts of the transcripts of most subunits of rat H+-ATP synthase examined greatly differed in the different tissues, showing the following hierarchy of tissue-specificity: heart > kidney > brain approximately liver. However, surprisingly, there was no difference in the expression pattern of these in terms of the molar ratio of each transcript, indicating a nearly similar stoichiometric expression pattern irrespective of tissue or age of the rat. Therefore, the present finding clearly indicates that most of the transcripts of the 16 subunits of rat H+-ATP synthase were concertedly and synchronously expressed, having a constant expression pattern of the transcripts, irrespective of tissue or age of the rats. This is the first report of the absolute amounts of the transcripts of this multisubunit enzyme.

Gene expression of subunit c(P1), subunit c(P2), and oligomycin sensitivity-conferring protein may play a key role in biogenesis of H+-ATP synthase in various rat tissues

Mammalian H+-ATP synthase is a supramolecule composed of at least 14 subunits that have a constant stoichiometry. Nevertheless the coordinate regulation of the gene expressions of various subunits remains obscure. To clarify the coordinate transcriptional regulatory system of mammalian H+-ATP synthase, we determined the absolute amount of nine species of mRNAs for eight nuclear-encoded subunits of H+-ATP synthase in different tissues of 8-week-old rats by use of the synthetic mRNAs and 32P-labeled DNA probes for each mRNA. Our quantitative analyses of the transcripts of H+-ATP synthase revealed that nine species of the subunits in different tissues of 8-week-old rats were divisible into two groups: a high transcript gene (HTG) group (beta-subunit, subunit b, subunit d, subunit e, and Factor 6) and a low transcript gene (LTG) group (subunit c(P1), subunit c(P2), IF1, and oligomycin sensitivity-conferring protein). The transcription step of LTG could constitute a bottleneck in the biogenesis of H+-ATP synthase. Thus, the transcriptional regulatory system of the LTG may play a key role in the biogenesis of mammalian H+-ATP synthase. The HTG were transcribed in a tissue-specific manner that corresponds with energy demand in the tissues. However, there was no tissue specificity in subunit c(P2). Furthermore, the tissue specificity of the transcript of IF1 differed substantially from that of HTG, suggesting that it could be crucial in the protection of mitochondrial membrane under abnormal conditions.

Molecular cloning and sequence of two cDNAs for human subunit c of H(+)-ATP synthase in mitochondria

Two cDNAs encoding different signal peptides (61 and 66 amino acid residues) and the same mature protein have been cloned from a human cDNA library with a rat subunit c cDNA. The amino acid sequence of the mature human subunit c of mitochondrial H(+)-ATP synthase was completely identical with those of the mature bovine, sheep and rat subunit c.

Molecular cloning and sequence of cDNAs for the import precursors of oligomycin sensitivity conferring protein, ATPase inhibitor protein, and subunit c of H(+)-ATP synthase in rat mitochondria

Four cDNAs for the import precursors of oligomycin sensitivity conferring protein (OSCP), ATPase inhibitor protein (IF1) and subunit cs (encoded by P1 and P2 genes) of rat mitochondrial H(+)-ATP synthase have been cloned from a rat cDNA library. The import precursors and the mature polypeptides of rat OSCP, IF1, subunit c (P1) and subunit c (P2) consisted of 23/190, 25/82, 61/75 and 66/75 amino acids, respectively.

cDNA cloning for and preparation of antibodies against subunit d of H(+)-ATP synthase in rat mitochondria

The cDNA for subunit d of rat mitochondrial H(+)-ATP synthase was cloned from a brain cDNA library. The protein contains internally repeat structures that have sequences similar to those of other ATP-related proteins. The antibodies raised against the protein A-subunit d fusion protein expressed in E. coli specifically recognized only the protein in the mitochondria. The Na2 CO3 fractionation followed by immunoblotting analyses suggest that at least a part of the protein is inserted into the membrane.

Analysis of the polyadenylation consensus sequence context in the genes of nuclear encoded mitochondrial proteins

A compilation of the pre-mRNA ends of the genes of nuclear encoded mitochondrial proteins resulted in a consensus sequence of the type (T/A)NTTNNNNNTTTNAATAAA. Nucleotide positions +8, +13, +14, +16 and +17 downstream of the AATAAA sequence show also a predominance of nucleotide T. This consensus sequence suggests the importance of the immediate surroundings of the cannonical polyadenylation signal sequence AATAAA on the efficiency of the cleavage and polyadenylation of this specific group of pre-mRNAs.

Molecular cloning of cDNA for the import precursor of human subunit B of H(+)-ATP synthase in mitochondria

The nucleotide sequence of the import precursor of subunit b of human H(+)-ATP synthase has been determined from a recombinant cDNA clone isolated by screening a human kidney cDNA library with a cDNA for rat subunit b as a probe. The sequence was composed of 1,134 nucleotides including a coding region for the import precursor of subunit b and noncoding regions on the 5'- and 3'-sides. The import precursor of subunit b and its mature polypeptide deduced from the open reading frame were found to consist of 256 and 214 amino acid residues with molecular weights of 28,893 and 24,610, respectively. The presequence of 42 amino acids could be the import signal peptide for directing the protein into the mitochondrial matrix.

Molecular cloning of cDNA for the import precursor of human coupling factor 6 of H(+)-ATP synthase in mitochondria

The nucleotide sequence of the import precursor of coupling factor 6 (factor 6) of human H(+)-ATP synthase has been determined from a recombinant cDNA clone isolated by screening a human kidney cDNA library with a cDNA for rat factor 6 as a probe. The sequence was composed of 466 nucleotides including a coding region for the import precursor of factor 6 and noncoding regions on the 5'- and 3'-sides. The import precursor of factor 6 and its mature polypeptide deduced from the open reading frame were found to consist of 108 and 76 amino acid residues with molecular weights of 12,596 and 8,969, respectively. The presequence of 32 amino acids could be the import signal peptide for directing the protein into the mitochondrial matrix.

H(+)-ATP synthase from rat liver mitochondria. A simple, rapid purification method of the functional complex and its characterization

A novel, simple, and rapid preparative method for purification of rat liver H(+)-ATP synthase by anion-exchange HPLC was developed. The H(+)-ATP synthase purified had higher ATPase activity in the absence of added phospholipids than any preparation reported previously, and this activity was completely inhibited by oligomycin. When reconstituted into proteoliposomes, the H(+)-ATP synthase showed an ATP-dependent 8-anilinonaphthalene-1-sulfonate response and ATP-Pi exchange activity, both of which were also completely inhibited by oligomycin and an uncoupler, indicating the intactness of the H(+)-ATP synthase. An immunochemical study and a labeling experiment with N,N'-[14C]dicyclohexylcarbodiimide ([14C]DCCD) demonstrated the presence of chargerin II ( a product of mitochondrial A6L DNA) and DCCD-binding protein (subunit c) in the complex. The subunits of the complex were separated into 11 main fractions by reverse-phase HPLC, and 3 of them and the delta subunit in F1 were partially sequenced. A search for sequence homologies indicated that these components were subunit b, coupling factor 6, subunit delta, and subunit epsilon. This is the first report of the existence of subunit b, factor 6, and chargerin II in H(+)-ATP synthase purified from rat liver mitochondria.

Identification of F0 subunits in the rat liver mitochondrial F0F1-ATP synthase

In order to identify the subunits constituting the rat liver F0F1-ATP synthase, the complex prepared by selective extraction from the mitochondrial membranes with a detergent followed by purification on a sucrose gradient has been compared to that obtained by immunoprecipitation with an anti-F1 serum. The subunits present in both preparations that are assumed to be authentic components of the complex have been identified. The results show that the total rat liver F0F1-ATP synthase contains at least 13 different proteins, seven of which can be attributed to F0. The following F0 subunits have been identified: the subunit b (migrating as a 24 kDa band in SDS-PAGE), the oligomycin-sensitivity-conferring protein (20 kDa), and F6 (9 kDa) that have N-terminal sequences homologous to the beef-heart ones; the mtDNA encoded subunits 6 (20 kDa) and 8 (less than 7 kDa) that can be synthesized in isolated mitochondria; an additional 20 kDa protein that could be equivalent to the beef heart subunit d.