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C A Reynaud

Publications and source records attributed to C A Reynaud.

44 records · Page 3Linked to original sources
PubMed1980

Restriction mapping of cDNA recombinants including the adult chicken and duck globin messenger sequences: a comparative study.

A comparison of the organization of six avian adult globin messenger sequences is based on previously reported recombinant duck adult globin cDNA plasmids (Therwath et al., 1980) and the actual construction and characterization of pBR322 recombinant plasmids including the beta and the normal alpha A and alpha D chicken adult globin mRNA sequences. Identification of the cloned DNA was performed using hybridization-selection under conditions permitting complete purification in one step of the three globin mRNAs, and translation of the corresponding mRNA. Orientation of the globin insert in the vector was determined, taking into account the computer prediction of the restriction sites based on the known amino acid sequences of the three globin chains (Roizès and Pelaquier, 1980) and those actually observed, and by identification of restriction fragments using 3'-specific probes. Identification, orientation and restriction mapping of these cloned DNAs reveals extensive homologies in organisation of beta sequences between duck and chicken, as well as among the alpha sequences in every two possible combinations.

Animals↗
PubMed1979

On pre-messenger RNA and transcriptions. A review.

From the present review integrating old and new data emerge a few principles of gene expression in eukaryotes, and an infinite variety of possible mechanistic details generating the overal pattern. The few principles, most of which are not fundamentally new, may thus be summarized. 1) The eukaryotic genome is subdivided into transcriptional units: into transcriptons which are subject to individual activation controlled at DNA level. 2) Viral genomes may contain one or a few transcriptons, while cells of multicellular organisms contain from 3 x 10(3) in diptera up to an estimated 2 x 10(5) in birds and mammals. 3) Transcriptons may include one or several coding sequences. 4) Transcriptons vary considerably in size: in mammals and birds their size spectrum falls into the 2,000 to 20,000 bp range. 5) Units of coding information constituting one message (genes) and, possibly, units of regulative information are frequently broken up and stored within the transcripton in sub-genic blocks (of so far unknown significance) in general located at a certain distance from the 5' and 3' transcript terminals which are determined by the promotor and terminator signals. 6) The gene, in its specific definition as the functional unit underlying the phenotype, is in general constituted posttranscriptionally by the processing mechanisms from the mosaic of its genomic subunits in the transcripton; segments of coding, service and regulative sequences are recombined within themselves and with each other, polygenic transcripts separate into their unit messages. 7) Activated transcriptons produce pre-mRNA; these primary transcripts are colinear with the DNA of the transcriptional unit. 8) Primary pre-mRNA is processed into secondary pre-mRNA's by extragenic cleavage and intragenic ("splicing") processing, giving rise stepwise to functional mRNA. During this process chemical modifications as methylation, 5'-terminal capping and 3'-terminal polyadenylation take place. 9) Translation yields either potentially functional polypeptides or polycistronic polyproteins subject to further processing. 10) Processing is a regulated process; it involves many of the possible phases and mechanisms of post-transcriptional regulation (cf. 39, 40).

Animals↗
PubMedDate not supplied

Rearrangement of a chicken immunoglobulin gene occurs in the lymphoid lineage of transgenic mice.

Immunoglobulin (Ig) and T-cell antigen receptor genes rearrange through identical heptamer-nonamer recognition sequences during entry of cells into the B or T lymphoid lineage. A similar enzymatic machinery may be used to perform these highly cell-specific events in these two types of lymphoid cells. We have investigated what the signal may be that triggers the rearrangement of one or other of the receptor genes in B or T cells. Mice from three transgenic lines carrying two, four or twenty copies of the unrearranged chicken lambda light-chain locus were analysed. In all three lines the chicken Ig transgene rearranges in B cells; in the line with 20 copies, a rearranged fragment can also be detected in thymus DNA. We conclude that the inserted chicken light-chain locus in its natural configuration contains target sequences that permit specific rearrangement in mouse lymphoid B cells, but that this precise differentiation step may be deregulated in thymic cells when the physiological level of relevant information is experimentally altered.

Animals↗