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P Daubas

Publications and source records attributed to P Daubas.

36 records · Page 2Linked to original sources
PubMed1985

Genes for skeletal muscle myosin heavy chains are clustered and are not located on the same mouse chromosome as a cardiac myosin heavy chain gene.

Myosin heavy chain (MHC) genes are expressed as several distinct isoforms in a tissue- and stage-specific manner; three skeletal muscle MHC isoforms appear sequentially during development. We have isolated cDNA clones, identified by RNA blot hybridization and by nucleotide sequence determination as coding for portions of the embryonic (pMHC2.2), perinatal (pMHC16.2A), and alpha(V1) cardiac (pMHC141 and pMHC101) MHC isoforms. These four probes and the adult skeletal MHC probe (pMHC32) have been used on Southern blots of genomic DNA to detect restriction fragment length polymorphisms defining the alleles for these genes in mouse species Mus musculus and Mus spretus. In this way, we followed the segregation of skeletal and cardiac MHC genes in 42 offspring resulting from an interspecies backcross. We found that the embryonic, perinatal, and adult skeletal MHC genes are clustered on chromosome 11 near the locus nude, the skeletal and cardiac MHC genes do not cosegregate, and the alpha(V1) cardiac MHC gene is located on chromosome 14 close to Np-1. This result is in contrast to that for other contractile protein genes such as the alkali myosin light chain and the actin multigene families, which are dispersed in the genome.

Animals↗
PubMed1984

A single locus in the mouse encodes both myosin light chains 1 and 3, a second locus corresponds to a related pseudogene.

Two loci have been characterized in the mouse Mus musculus, which are homologous to the mRNAs encoding myosin light chains MLC1F and MLC3F, two proteins with a common -COOH terminal sequence. One of these loci is an intronless pseudogene, absent from the mouse species Mus spretus; alterations in its nucleotide sequence preclude it from generating a functional MLC1F or MLC3F. The other contains the genetic information for the two proteins. The part common to both proteins is encoded by five exons, which cover about 6.5 kb. Genetic information specific for the N-terminal sequences is encoded in four exons, at 3.5 and 14.3 kb for MLC1F, and 3.8 and 4.5 kb for MLC3F, upstream of the first common exon. Each 5' terminus has a TATA-like consensus sequence about 30 bases upstream of the cap site. The pseudogene is not genetically linked to the functional MLC1F/MLC3F locus in the genome of Mus musculus.

Amino Acid Sequence↗
PubMed1983

Sequential accumulation of mRNAs encoding different myosin heavy chain isoforms during skeletal muscle development in vivo detected with a recombinant plasmid identified as coding for an adult fast myosin heavy chain from mouse skeletal muscle.

In order to study developmental transitions of myosin heavy chain gene expression, we have cloned from newborn mouse skeletal muscle a recombinant plasmid (plasmid MHC 32) that contains an insertion coding for the COOH-terminal portion of an adult fast myosin heavy chain isoform of mouse skeletal muscle. By Northern blots and dot blots, it has been shown that the MHC 32 sequence reveals a broad cross-hybridization with RNA from different mammalian striated muscle tissues. Southern blots with mouse genomic DNA show only one homologous gene, but cross-hybridization at lower stringency to seven to eight different bands, some containing multiple genomic fragments, among which are probably the genes encoding the different striated muscle isoforms. S1 protection experiments with RNA from mouse skeletal muscle before and after birth demonstrate that plasmid MHC 32 is homologous to a major mRNA species of adult skeletal muscle. This adult mRNA is a predominant sequence within 5-6 days after birth. It begins to accumulate at 1-3 days; at the 18th day fetal stage, another major mRNA species is detected as partially homologous with the adult MHC 32 sequence. This fetal myosin heavy chain mRNA is still predominant at 1-3 days after birth, but is rapidly (by 5-6 days) replaced by the adult MHC sequence. There is thus a rapid transition after birth from fetal to adult skeletal muscle myosin heavy chain mRNA sequences.

Amino Acid Sequence↗
PubMed1982

A radioimmunoassay of human leukocyte interferon using protein A-containing Staphylococcus aureus.

We report the establishment of a radioimmune assay for human alpha-interferon using highly purified alpha-interferon labeled with iodine-125, a purified rabbit immunoglobulin directed against human interferon and the Cowan strain of Staphylococcus aureus. Radiolabeling conditions used do not change the antigenicity of interferon molecules. The regression of counts bound upon log. dose was found to be linear down to 10 units/ml of alpha-interferon (6-7 X10-12 M). This assay was specific for alpha-interferons derived from human peripheral blood leukocytes and from a continuous line of lymphoblastoid cells. No cross-reaction was found with either human beta-interferon or murine interferon. Neither human serum nor plasma interfered with the assay. Correlation between biological assay and radioimmune assay was found to be significant.

Animals↗
PubMed1982

cDNA recombinant plasmid complementary to mRNAs for light chains 1 and 3 of mouse skeletal muscle myosin.

A recombinant plasmid with a cDNA sequence transcribed from mouse skeletal muscle RNA is shown to hybridize with mRNAs for myosin light chains LC1F and LC3F. The inserted fragment corresponds exclusively to the 3'-noncoding region of the mRNA. It hybridizes almost exclusively with the two light chain messengers from fast skeletal muscle RNA of adult mouse. Slight hybridization is seen with RNA from heart muscle and embryonic skeletal muscle. The implications of the conservation of the 3'-noncoding regions between the two mRNAs are discussed.

Animals↗
PubMed1981

Muscle coding sequences and their regulation during myogenesis: cloning of muscle actin cDNA probes.

For a number of years our group has been mainly interested in the regulation of muscle gene expression during myogenesis. Using primary cultures and cell lines we have tried to find out whether the coding sequences for muscle proteins are already present in an unexpressed form or if there is a transcriptional switch at the onset of differentiation. Metabolic studies on pulse-labelled RNA, together with translation and molecular hybridization experiments have given a certain number of indications. More recently the development of genetic engineering techniques has made it possible to answer these questions directly with probes which are complementary to specific muscle coding sequences. We have identified a plasmid which contains a coding sequence for muscle actin. Other recombinant plasmids are being characterized. Such plasmids, used as probes, will permit us to study the organization and expression of the genes coding for the contractile proteins in muscle cells.

Actins↗
PubMed1979

Biochemical aspects of muscle differentiation as analyzed by in vitro cultivation techniques.

Myoblasts cultivated in vitro will undergo terminal differentiation to form muscle fibres. Teratoma derived mouse cell lines, a pluripotent primitive line, and a muscle cell line, provide a possibility for comparing RNA populations in an early precursor cell with those in committed myoblasts and differentiated myotubes. Molecular hybridization analyses led to the conclusion that new RNA sequences appear in the cytoplasm during muscle differentiation. Such muscle specific sequences are not detectable in the nuclear RNA of myoblasts or primitive cells. Studies of protein synthesis during terminal myogenesis indicate co-ordinate expression of the muscle contractile proteins. These represent distinct isozymes, distinguishable from the contractile proteins of other cell types. In the case of myosin light chains isozymic transitions between different muscle forms have been identified during early development.

Animals↗
PubMedDate not supplied

Investigation of genetic linkage between myosin and actin genes using an interspecific mouse back-cross.

The introduction of cloned probes to follow the segregation of DNA restriction fragment length polymorphisms (RFLPs) has led to a revival of mendelian genetics in attempts to map the human genome. In the mouse, however, it has often proved difficult to detect an RFLP with a DNA probe between different inbred strains of the laboratory mouse. To circumvent this problem, we have used two species, Mus musculus domesticus and Mus spretus which interact as sympatric species but can be interbred under laboratory conditions. Because of the relative evolutionary distance between these species, they exhibit polymorphism at many more loci than do different strains of the usual M. m. domesticus laboratory mouse. This is also observed at the DNA level when the sizes of restriction fragments encoding a specific gene are compared. We have used these RFLPs between M. m. domesticus and M. spretus to follow the segregation of genes encoding different isoforms of myosin alkali light chains in the backcross progeny between these species and to compare this with that of other contractile protein genes. No linkage between these genes was observed.

Actins↗
PubMedDate not supplied

[Cornea and anterior chamber implant with flexible closed haptics].

Authors report the result of 148 cases of flexible (with closed haptics) anterior chamber lens implantation. Analysis of per and post-operative corneal complications, Study shows increase in time of such complications, in relation to secondary displacement and alteration of lens shape.

Adult↗
PubMedDate not supplied

["Bell clappers" with "ophthalmologic alarm". Apropos of 2 cases of colloid cysts of the 3d ventricle].

We report two cases of third ventricle colloid cyst in atypical adult's neurological descriptions, tracked down by ophthalmologist, proved by computed tomography and magnetic resonance imaging. We describe physio-pathological mechanism and dwell on different ophthalmological events of exceptional occurrence with those benign tumours and on ophthalmological investigation's importance in case of persisting and unexplained headache. We conclude with spontaneous clinical course, and neurological surgery's efficacy on hydrocephalus.

Adult↗