Growth metabolism of diaphragm in Swiss albino mice

Summary During the postnatal growth of diaphragm in swiss albino mice, a continuous decline in glycogen content reciprocates with the increasing SDH-activity and protein accumulation. An inverse relationship between DNA-contents and the basic protein levels points towards the regulatory behaviour of the latter during protein synthesis. While the variations in the contents of DNA and RNA speak of a feedback mechanism operative between the 2 nucleic acids during the postnatal growth, the fluctuations in RNA appear to be significant in determining the amount of acidic proteins, in this muscle.     

Villus growth and cell replacement in the small intestine of the neonatal pig

Cells produced in the crypts of newborn pig ileum migrate onto villi during development. There is little or no corresponding loss of cells from villus tips during the first week of postnatal life. Villus growth during this period is largely responsible for the slow rate of cellular renewal seen to take place.     

Villus growth and cell replacement in the small intestine of the neonatal pig

Summary Cells produced in the crypts of newborn pig ileum migrate onto villi during development. There is little or no corresponding loss of cells from villus tips during the first week of postnatal life. Villus growth during this period is largely responsible for the slow rate of cellular renewal seen to take place.     

Chromosome change during growth inPuschkinia libanotica L. (Liliaceae)

Summary The variation in chromosome size in root-tip meristem ofPuschkinia libanotica L. was studied at different days of root growth with special attention to DNA, RNA, total protein and histone contents. The results show that the size and organisation of chromosomes even within the one tissue is subject to considerable change during growth and development.The author is thankful to Prof. H. Rees, FRS, Department of Agricultural Botany, University College of Wales, Aberystwyth, Wales, U.K., for his guidance and to University College of Wales, Aberystwyth, for granting him a SRC fellowship.     

Protection from body weight loss by 2-mercaptopropionylglycine (MPG) in growing mice irradiated in utero with gamma radiation

Summary 2-Mercaptopropionylglycine administered during fetal growth period, protected significantly young mice against loss of body weight during postnatal development induced by 50 R gamma irradiation.Acknowledgment. The work was supported by a grant from CSIR, New Delhi, to P.K.D. which is gratefully acknowledged. The authors are also thankful to Prof. P. Navlakha for the irradiation facilities.     

Regulatory mechanisms of RNA function: emerging roles of DNA repair enzymes

The acquisition of an appropriate set of chemical modifications is required in order to establish correct structure of RNA molecules, and essential for their function. Modification of RNA bases affects RNA maturation, RNA processing, RNA quality control, and protein translation. Some RNA modifications are directly involved in the regulation of these processes. RNA epigenetics is emerging as a mechanism to achieve dynamic regulation of RNA function. Other modifications may prevent or be a signal for degradation. All types of RNA species are subject to processing or degradation, and numerous cellular mechanisms are involved. Unexpectedly, several studies during the last decade have established a connection between DNA and RNA surveillance mechanisms in eukaryotes. Several proteins that respond to DNA damage, either to process or to signal the presence of damaged DNA, have been shown to participate in RNA quality control, turnover or processing. Some enzymes that repair DNA damage may also process modified RNA substrates. In this review, we give an overview of the DNA repair proteins that function in RNA metabolism. We also discuss the roles of two base excision repair enzymes, SMUG1 and APE1, in RNA quality control.     

A quick and efficient method to generate mammalian stable cell lines based on a novel inducible alphavirus DNA/RNA layered system

We report a new method to generate high-expressing mammalian cell lines in a quick and efficient way. For that purpose, we developed a master cell line (MCL) containing an inducible alphavirus vector expressing GFP integrated into the genome. In the MCL, recombinant RNA levels increased >4,600-fold after induction, due to a doxycycline-dependent RNA amplification loop. The MCL maintained inducibility and expression during 50 passages, being more efficient for protein expression than a conventional cell line. To generate new cell lines, mutant LoxP sites were inserted into the MCL, allowing transgene and selection gene exchange by Cre-directed recombination, leading to quick generation of inducible cell lines expressing proteins of therapeutic interest, like human cardiotrophin-1 and oncostatin-M at several mg/l/24 h. These proteins contained posttranslational modifications, showed bioactivity, and were efficiently purified. Remarkably, this system allowed production of toxic proteins, like oncostatin-M, since cells able to express it could be grown to the desired amount before induction. These cell lines were easily adapted to growth in suspension, making this methodology very attractive for therapeutic protein production.     

Nerve growth factor selectively stimulates the degradation of chondromucoprotein in the embryonic cartilage in vitro.

Nerve growth factor specifically stimulates the degradation of chondromucoprotein in the chick embryonic cartilage cultivated in vitro, with little effect on chondromucoprotein, RNA, DNA and protein synthesis.     

Estrogenic inhibition of testicular growth by R2858 in preweanling rats

Daily injections of physiologic doses of R2858 into preweanling rats from the 10th to the 19th day of age resulted in reduced testicular growth compared to controls. Body weights and other organ weights were unaffected. Leydig cells were smaller and less numerous, and showed distinct changes in ultrastructural morphology. Results of this study suggest that alpha-fetoprotein permits normal testicular development during postnatal life.     

Unchanged r-RNA-gene dose in mice liver cells of different developmental stages.

The content of ribosomal DNA in mice liver at the beginning as well as near the end of the hematopoietic period was measured by RNA/DAN-hybridization in solution. At both stages the amount of ribosomal DNA was the same and comparable to that of postnatal liver.     

Structure-function relationships of the polypyrimidine tract binding protein

The polypyrimidine tract binding protein (PTB) is a 58-kDa RNA binding protein involved in multiple aspects of mRNA metabolism including splicing regulation, polyadenylation, 3′end formation, internal ribosomal entry site-mediated translation, RNA localization and stability. PTB contains four RNA recognition motifs (RRMs) separated by three linkers. In this review we summarize structural information on PTB in solution that has been gathered during the past 7 years using NMR spectroscopy and small-angle X-ray scattering. The structures of all RRMs of PTB in their free state and in complex with short pyrimidine tracts, as well as a structural model of PTB RRM2 in complex with a peptide, revealed unusual structural features that provided new insights into the mechanisms of action of PTB in the different processes of RNA metabolism and in particular splicing regulation. Received 16 August 2007; received after revision 18 September 2007; accepted 2 October 2007     

Die Veränderung des Stärke-, Protein- und RNS-Gehaltes vonLemna minor L. unter dem Einfluss von Kinetin (6-Furfurylaminopurin)

Summary Kinetin (6-furfurylaminopurine) is rapidly absorbed byLemna minor L. 3 · 10^–8 M/ml medium cause an immediate but temporary stimulation of RNA and protein synthesis during the first hour of the treatment. The following excessive accumulation of starch is considered to be more or less a direct consequence of a disturbed RNA and protein metabolism.     

Relationship between polyamine accumulation and RNA biosynthesis and content during the cell cycle

Polyamine accumulation was related to RNA biosynthesis and content during the cell cycle of CHO-K1 and HeLa cells. The highest correlations were observed between polyamine accumulation and RNA content. Feeding, serum-starved cultures of embryonic chick fibroblasts, which exhibit a 3-fold increase in RNA content, demonstrated that RNA content was most closely paralleled by spermidine content.     

Sex-dependent action of prenatal fractionated X-irradiation in the mouse. Biochemical findings.

X-irradiation of pregnant NMRI-mice on gestational days 11-13 with 3 x 10.5 Gy increased postnatal mortality of the female offspring only. Weights, protein content and acetylcholinesterase, as well as Na,K-ATPase activities in the brains of all treated offspring, were changed. There were, however, no differences between females and males with respect to these parameters.     

Roles for CCN2 in normal physiological processes

CCN2, also known as connective tissue growth factor, is a member of the CCN (CCN1–6) family of modular matricellular proteins. Analysis of CCN2 function in vivo has focused primarily on its key role as a mediator of excess ECM synthesis in multiple fibrotic diseases. However, CCN2 and related family members are widely expressed during development. Recent studies using new genetic models are revealing that CCN2 has essential roles in the development of many tissues. This review focuses on current and emerging data on CCN2 and its functions in chondrogenesis and angiogenesis, and on new studies showing that CCN2 has essential functions during embryonic and postnatal development in a number of epithelial tissues.     

Maternal vitamin A restriction alters biochemical development of the brain in rats.

The biochemical development of the fetal brain in relation to maternal vitamin A restriction was studied in rats. The vitamin A status of pregnant rats was varied by supplying low, medium and adequate amounts (6, 40, and 100 micrograms retinol/day/kg body weight, respectively) of vitamin A during pregnancy and suckling. The maternal vitamin A restriction caused an altered brain development in terms of tissue weight, DNA, RNA and protein levels, and biosynthesis of DNA and protein from [3H]-thymidine and [3H]-leucine, respectively. A dose-dependent effect of maternal vitamin A restriction on the metabolism of DNA, RNA and protein was noticed in the developing fetal brain of rats.     

Editing porcine <Emphasis Type="Italic">IGF2</Emphasis> regulatory element improved meat production in Chinese Bama pigs

Insulin-like growth factor 2 (IGF2) is an important growth factor, which promotes growth and development in mammals during fetal and postnatal stages. Using CRISPR–Cas9 system, we generated multiple founder pigs containing 12 different mutant alleles around a regulatory element within the intron 3 of IGF2 gene. Crossing two male founders passed four mutant alleles onto F1 generation, and these mutations abolished repressor ZBED6 binding and rendered this regulatory element nonfunctional. Both founders and F1 animals showed significantly faster growth, without affecting meat quality. These results indicated that editing IGF2 intron 3–3072 site using CRISPR–Cas9 technology improved meat production in Bama pigs. This is the first demonstration that editing non-coding region can improve economic traits in livestock.     

Relationship between polyamine accumulation and RNA biosynthesis and content during the cell cycle

Summary Polyamine accumulation was related to RNA biosynthesis and content during the cell cycle of CHO-K1 and HeLa cells. The highest correlations were observed between polyamine accumulation and RNA content. Feeding, serumstarved cultures of embryonic chick fibroblasts, which exhibit a 3-fold increase in RNA content, demonstrated that RNA content was most closely paralleled by spermidine content.I acknowledge the receipt of a Medical Research Council studentship.