Acetylcholinesterase differentiation during myogenesis in early chick embryonic cells caused by an inducer RNA

Therapeutic Effects of Ribunucleinate (Ribonucleotides) in Immuno-Inflammatory and Arthritic Diseases

Ribonucleic acids from different organs and from yeast have been used for the treatment of chronic and degenerative diseases in the context of naturopathic medicine in the last 60 years. This chapter provides general information about ribonucleinates as therapeutic agents. Past and present pharmacological and clinical investigations are discussed in the field of the central nervous system, sensory organs, cancer and degenerative diseases of joints and vertebra.

Sheep heart RNA stimulates myofibril formation and beating in cardiac mutant axolotl hearts in organ culture

In the Mexican axolotl, Ambystoma mexicanum, recessive mutant gene c, when homozygous, results in a failure of the heart to form sarcomeric myofibrils and contract normally. Previous studies have shown that purified RNA from normal anterior endoderm or from medium conditioned with anterior endoderm/pre-cardiac mesoderm has the capacity to rescue mutant hearts in organ culture. In the present study, RNA extracted from adult sheep heart was tested for its capacity to promote differentiation in the mutant axolotl hearts. Mutant hearts cultured in the presence of the sheep heart RNA in Steinberg's solution for 48 h displayed rhythmic contractions. Ultrastructural studies showed that the rescued mutant axolotl ventricular myocardial cells contained myofibrils of normal morphology. Mutant hearts cultured in Steinberg's solution alone did not beat throughout their lengths and myofibrils were not observable in the ventricles. Confocal microscopy confirmed the increase of Tropomyosin expression and formation of myofibrils in mutant hearts treated by sheep heart RNA. Thus, sheep heart RNA promotes myofibrillogenesis and the development of contractile function in embryonic cardiac mutant axolotl hearts.

Cardiac differentiation induced by dopamine in undifferentiated cells of early chick embryo

Evidence suggests that neurotransmitters can act as possible chemical signals involved in cell division and morphogenetic movements long before neurons appear in the embryo. However, whether they are playing a role in differentiation is now unknown. It was recently observed (M. Sarasa and S. Climent, 1987, J. Exp. Zool. 241, 181-190) that the neurotransmitter dopamine exerted a stimulating effect on cardiac differentiation in the chick in ovo. We show here that dopamine acts as a specific inducer of heart muscle differentiation in vitro. When cells of the gastrula of embryos treated with dopamine were dissociated and reaggregated, the aggregates obtained almost entirely underwent cardiac muscle differentiation. Also, when small postnodal pieces obtained from the most posterior region of the gastrula were cultivated in the presence of dopamine, they differentiated into myocardic tissue instead of following their fate map. Therefore, dopamine can trigger a process that both causes undifferentiated cells to differentiate into heart muscle and compels cells already determined to another way of differentiation to become myocardic tissue.

Co-ordinate control of gene expression. Muscle-specific 7 S RNA contains sequences homologous to 3'-untranslated regions of myosin genes and repetitive DNA

We have cloned and sequenced a complementary DNA copy (pSS48) of a novel muscle-specific, low molecular weight RNA, 7 S RNA, isolated from embryonic chick cardiac muscle cells. The hybridization pattern of plasmid pSS48 DNA to chick genomic DNA suggests that 7 S RNA is derived from the repetitive chick DNA with a repetition frequency of about 300 copies per haploid genome. Under low stringency, pSS48 DNA also hybridizes with high specificity to the single copy gene for chick myosin light chain (MLC) and to myosin heavy chain (MHC), and possibly to other co-ordinately expressed genes for chick muscle proteins. The sequence analysis of recombinant plasmids pSS48, pML10 and pMHC8, for 7 S RNA, MLC mRNA and MHC RNA, respectively, indicated that short nucleotide stretches homologous to 7 S RNA reside in the 3' untranslated regions of the respective genes. The 7 S RNA sequence appears to be highly specific for the chick muscle tissue, since RNA and DNA from several sources did not hybridize to pSS48 DNA. Furthermore, the 7 S RNA-like sequence(s) appears in chick blastodermal cells preferentially earlier than the onset of transcription of genes for major muscle proteins. These results, taken together, suggest a possible function for 7 S RNA in expression of muscle-specific genes during chick development.

Cloning of synthetic deoxyribonucleic acid that codes for embryonic cardiac myosin light-chain polypeptide

Double-stranded complementary deoxyribonucleic acid (cDNA) transcribed in vitro from a partially pure myosin light-chain messenger ribonucleic acid (mRNA) of the chick embryonic heart was cloned in Escherichia coli strain chi 1776 by using the HindIII cleavage site in the plasmid pBR322. The insertion of essentially full length DNA was achieved by repeated selection of large-size cDNA transcripts. Of the 12 transformants that contained large-size DNA inserts, the clone pML10 insert was 950 base pairs in length, almost the same size as myosin light-chain mRNA (980 nucleosides). The clone pML10 was identified by hybridization with a highly pure cDNA probe and by hybrid-arrested translation assay. pML10 was further characterized by partial restriction enzyme mapping. The availability of a cloned DNA probe for myosin light-chain facilitates the analysis of the mechanism underlying the induction of cardiac muscle specific gene transcription in presumptive heart-forming cells of the chick blastoderm.

Human lymphoblastoid cells in culture replicate immune information carried by xenogeneic RNA

Immune RNA is obtained from lymphoid organs of immunized animals and is reputed to transfer immunological information. Human lymphoblastoid cells in culture, after incubation with sheep Immune RNA produce RNA (Ic-RNA) which carries the same immunological information as the inducing sheep preparation. This Ic-RNA produced in tissue culture is capable of converting 'naive' human lymphocytes to cytotoxic effector cells against tumour target cells, to the same extent as the Is-RNA preparation used for induction of the cell line. The sheep Immune RNA information is present and can be recovered from the lymphoblastoid cells for at least ten weeks after the induction. It is suggested that xenogeneic Immune RNA information is incorporated in a stable fashion by cultured human lymphoblastoid cells, and also that it is replicated during their own replication. This system could be used for studying the incorporation of information carried by exogenous RNA and it might provide insight into some mechanisms underlying the transfer and processing of immunological information.