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

Abstract

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 1 -ATP synthase examined greatly differed in the different tissues, showing the following hierarchy of tissue-specificity: heart . kidney . brain < 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 1 -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.Keywords: H 1 -ATP synthase; expression pattern; transcript; stoichiometry; synchronization.The mechanism of the transcriptional regulation of the genes involved in the biosynthesis and assembly of multisubunit mitochondrial enzyme complexes, e.g. [14,17±18a]. Subunit a and A6L are encoded by the mitochondrial genome, and all of the other subunits are separately encoded by nuclear chromosomes; however, the relationship between the stoichiometry of polypeptides of the complexes and the absolute amount of each transcript of this multisubunit enzyme complex in mammalian tissues is still entirely unknown.In the present work, we determined the absolute amount of nine species of mRNAs for eight nucleus-encoded subunits of H 1 -ATP synthase in the brain, liver, heart, and kidney tissues of 2-week-old to 90-week-old male Fischer 344 rats by using highly purified poly(A) 1 RNA and the mRNAs synthesized by an in vitro transcriptional system. M A T E R I A L S A N D M E T H O D S AnimalsMale Fischer 344 rats were obtained from Charles River Japan Inc (Atsugi, Japan), and were genetically identical because of approximately 300 matings between sister and brother. Purification of Poly(A)1 RNAThe rats were decapitated, and tissues of brain, liver, heart, and kidney were rapidly removed. Total RNA from these tissues was isolated by the guanidinium thiocyanate method [19], followed by centrifugation at 120 000 g for 24 h in 5.7 m CsCl solution and then extraction with acid phenol. The poly(A) 1 RNA was purified with Oligotex-dT30 (Takara) according to the manufacturer's instructions, and the purification steps with Oligotex-dT30 were repeated twice. The poly(A) 1 RNA eluted from the 2nd Oligotex-dT30 was extracted with acid phenol, precipitated with 70% ethanol, dried, and dissolved in diethyl pyrocarbonate-treated water. The amount of poly(A) 1 RNA was determined from the absorbance at 260 nm (one unit of absorbance at 260 nm 40 mg´mL 21). The A260/A280 ratios were in the range 1.8±2.0. Contamination by ribosoma...

Changes of carp FoF1-ATPase in association with temperature acclimation

“…Considering sequence diversity in the predicted signal part of the c-F o -ATPase, it appears that the cloned cDNA of carp in the present study correspond to the P3 isoform of zebrafish c-F o -ATPase, which showed 96% identity in the amino acid sequence. Although P1 and P2 isoforms have been found in mammalian c-F o -ATPase (3,15,35) and Fugu genome database (Scaffold_1299 for P1 and Scaffold_6377 for P2), such isoforms could not be detected in carp fast muscle in this study. The fact that the mature c-F o -ATPase irrespective of isoforms were almost completely conserved among vertebrates including carp (see Fig.…”

Investigation of Differentially Expressed Genes in the Ventricular Myocardium of Senescent Rats

“…ATP synthase is a key enzyme in oxidative phosphorylation and responsible for the production of most of the ATP in mammalian organisms. The absolute amounts of the transcripts of most subunits of rat H + ‐ATP synthase examined differed greatly in different tissues, showing the following hierarchy of tissue specificity: heart > kidney > brain, liver 9 . We demonstrated here that one of the ATP synthase subunits is downregulated in senescent heart.…”

“…The absolute amounts of the transcripts of most subunits of rat H + -ATP synthase examined differed greatly in different tissues, showing the following hierarchy of tissue specificity: heart > kidney > brain, liver. 9 We demonstrated here that one of the ATP synthase subunits is downregulated in senescent heart. ATP synthase expression was reported to be decreased in the heart of those with chronic nicotine consumption, 10 while increased in the norepinephrine-infused hypertrophic heart.…”