Transcription of the non-repetitive genome in liver hypertrophy and the homology between nuclear RNA of normal and 12 H-regenerating liver

Tedeschi, M.Valeria; Colbert, Donald A.; Fausto, Nelson

doi:10.1016/0005-2787(78)90305-2

Cited by 19 publications

(12 citation statements)

References 17 publications

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“…Liver regeneration is one of the best-studied examples of compensatory growth in mammals and is a well-defined model for examining the role of proto-oncogenes in non-neoplastic cellular growth (7). Whereas initial studies focused on general changes in the amount of liver mRNA and the average transcript size during liver regeneration (8)(9)(10)(11), advances in recombinant DNA technology have made it possible to study the regulation of specific mRNAs in normal and regenerating liver. Despite the close qualitative homology be-tween polysomal poly(A)+ mRNA populations in normal and regenerating rat liver, obvious differences have been revealed in the abundance of certain proto-oncogene transcripts in these populations (12)(13)(14).…”

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confidence: 99%

Cellular analysis of c-Ha- ras gene expression in rat liver after CCl4 administration

et al. 1989

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Expression of the c-Ha-ras proto-oncogene is specifically enhanced during liver regeneration, in parallel with increased DNA replication, which suggests that c-Ha-ras may play a role in the control of regeneration. In this study, an in situ hybridization technique was applied for analysis of expression of the c-Ha-ras gene at the cellular level during liver regeneration induced by CCl4 administration. The in situ hybridization was compared with the observation for the p21c-Ha-ras protein, the corresponding protein of the c-Ha-ras gene, by immunohistochemistry. In normal rat liver, a few hepatocytes expressed the mRNAs and the corresponding proteins without any preferential localization. Zonal heterogeneity of c-Ha-ras gene expression first became evident at 12 hr after CCl4 administration, a higher number of gene products being detected in the pericentral zone than in the periportal zone. This heterogeneity became maximal at 24 hr after CCl4 administration. Zonal heterogeneity in the level of the p21c-Ha-ras protein paralleled that in the level of gene expression. Furthermore, both hepatocytes and nonparenchymal cells participated in expression of the c-Ha-ras gene during liver regeneration.

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confidence: 99%

Cellular analysis of c-Ha- ras gene expression in rat liver after CCl4 administration

et al. 1989

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“…However, the total complexity, which corresponds to approx. 15000 different mRNA sequences (Colbert et at., 1977;Tedeschi et al, 1978), remains the same as that of sham-operated rats. Given these results, it is conceivable that mRNA deficits in the regenerating liver of protein-deprived rats represent alterations in the abundance of mRNA sequences rather than a change in the complexity of the mRNA population.…”

Section: Discussionmentioning

confidence: 59%

“…Polyribosomal fractions were stored at -70°C until analysed. RNA extractions and separation of polyadenylated mRNA were carried out as previously described (Colbert et al, 1977;Tedeschi et al, 1978).…”

Section: Polyribosomes and Rna Extractionsmentioning

confidence: 99%

“…Free and bound polyribosomes were prepared from the livers of ten rats in each dietary group. Nuclear RNA was extracted with phenol as described by Tedeschi et al (1978) and was not fractionated further. RNA extracted from free and bound polyribosomes was separated into polyadenylated and non-adenylated RNA fractions by chromatography on poly(U)-Sepharose.…”

Section: Daymentioning

confidence: 99%

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Effects of protein-deprivation on the regeneration of rat liver after partial hepatectomy

McGowan¹,

Atryzek²,

Fausto³

1979

Biochemical Journal

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Rats maintained on a protein-free diet for 3 days have an altered time course of hepatic DNA synthesis during liver regeneration. The delay in DNA synthesis is eliminated by the administration of casein hydrolysate (given as late as 6h after partial hepatectomy), but not by glucose or incomplete amino acid mixtures. Despite the change in the timing of DNA synthesis, the increases in hepatic amino acid pools, which take place at the earliest stages of the regenerative process, occur in a normal pattern in the regenerating liver of rats fed the protein-free diet. Protein-deprived rats have increased protein synthesis and decreased rates of protein degradation in the liver in response to partial hepatectomy, but these adaptations do not prevent a lag in protein accumulation and low protein/RNA ratios. The regenerating livers of these animals show a deficit in the accumulation of cytoplasmic polyadenylated mRNA as well as a smaller proportion of free polyribosomes. It is suggested that the deficit in free polyribosomes found in the regenerating liver of protein-deprived rats might be a consequence of the slow accumulation of mRNA species coding for intracellular proteins.

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“…The diversity or complexity of an RNA population can be measured by hybridizing RNA in excess to trace amounts of radioactive, nonrepetitive (unique-sequence) DNA, such that the amount of DNA driven into hybrids at saturation gives a direct measure of the percentage of nonrepetitive DNA transcribed. Complexity measurements have consistently shown that brain RNA in rodents displays a greater complexity than RNA from other tissues (mouse tissue [2,6,15,16,19,26,49]; rat tissue [8,9,13,14,17,25,28,43,47,51]). For example, Chikaraishi et al (9) have found the nuclear RNA complexity of rat brain (31.2% of unique-sequence DNA coding capacity, assuming asymmetric transcription) to be higher than that of liver (21.8%) or kidney (10.6%).…”

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confidence: 99%

Cloning of DNA corresponding to rare transcripts of rat brain: evidence of transcriptional and post-transcriptional control and of the existence of nonpolyadenylated transcripts.

Brilliant¹,

Sueoka²,

Chikaraishi³

1984

Mol. Cell. Biol.

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To examine the expression of genes encoding rare transcripts in the rat brain, we have characterized genomic DNA clones corresponding to this class. In brain cells, as in all cell types, rare transcripts constitute the majority of different sequences transcribed. Moreover, when compared with other tissues or cultured cells, brain tissue may be expected to have an even larger set of rare transcripts, some of which could be restricted to subpopulations of neural cells. We have identified seven clones whose transcripts are nonabundant, averaging less than three copies per cell. Clone rgl3 (rat genomic 13) RNA was detected only in the brain, whereas RNA of a second clone, rg4O, was also detected in the brain and in a melanoma. Transcripts of rgl3 were found in cerebellum, cerebral cortex, and regions underlying the cortex, whereas rg4O transcripts were not detected in the cerebellum. Transcripts of both rgl3 and rg4O were found in pelleted polysomal RNA. RNA of another clone, rg34, was found in the brain, liver, and kidney but was found in pelleted polysomal RNA only in the brain, suggesting that its expression may be post-transcriptionally controlled. The remaining four clones represent rare transcripts that are common to the brain, liver, and kidney; rgl8 RNA is restricted to the nucleus, whereas rg3, rg26, and rg36 transcripts are found in the cytoplasm of all three tissues. Transcripts of the brain-specific clone, rgl3, and the commonly expressed clone, rg3, are nonpolyadenylated, presumably belonging to the high-complexity, nonpolyadenylated class of transcripts in the mammalian brain.The mammalian brain, the most complex organ in terms of function and structure, is also the most complex in terms of the diversity of its transcripts. The diversity or complexity of an RNA population can be measured by hybridizing RNA in excess to trace amounts of radioactive, nonrepetitive (unique-sequence) DNA, such that the amount of DNA driven into hybrids at saturation gives a direct measure of the percentage of nonrepetitive DNA transcribed. Complexity measurements have consistently shown that brain RNA in rodents displays a greater complexity than RNA from other tissues (mouse tissue [2,6,15,16,19,26,49]; rat tissue [8,9,13,14,17,25,28,43,47,51]). For example, Chikaraishi et al. (9) have found the nuclear RNA complexity of rat brain (31.2% of unique-sequence DNA coding capacity, assuming asymmetric transcription) to be higher than that of liver (21.8%) or kidney (10.6%).A higher proportion of nuclear RNA complexity (nearly two-thirds) is conserved as cytoplasmic or polysomal RNA in the brain than in the liver or kidney (3, 8)

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Transcription of the non-repetitive genome in liver hypertrophy and the homology between nuclear RNA of normal and 12 H-regenerating liver

Cited by 19 publications

References 17 publications

Cellular analysis of c-Ha- ras gene expression in rat liver after CCl4 administration

Cellular analysis of c-Ha- ras gene expression in rat liver after CCl4 administration

Effects of protein-deprivation on the regeneration of rat liver after partial hepatectomy

Cloning of DNA corresponding to rare transcripts of rat brain: evidence of transcriptional and post-transcriptional control and of the existence of nonpolyadenylated transcripts.

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