Structural organization of the rat gene for the arginine vasopressin-neurophysin precursor

[This corrects the article on p. 763 in vol. 2, PMID: 6315416.].     

Structural organization of the 3'' half of the rat thyroglobulin gene

We report the structural organization of an 80 Kb segment of rat DNA, which encodes for about 40% of Thyroglobulin mRNA at the 3' end. The codogenic information included in this segment is splitted in 17 exons of homogeneous size (about 200 bp). The seven exons at the extreme 3' end have been precisely defined by DNA sequence analysis. No clear sequence homology is found among the exons, even though their coding capacity is quite similar, from 55 to 63 aminoacids residues. We located 2 hormonogenic (T4 forming) sites on the extreme 3' end of the gene in different exons. The DNA sequence coding for these functional sites shows a 70% homology in a 50 nucleotides segment. In addition we found a remnant of this sequence in other exons of the gene. Two large introns have been found on the 3' end of the gene: one is 17 Kb and the other one is more than 30 Kb long. On the basis of these findings and of preliminary studies on the remaining 5' end of the gene, we can predict that the minimum length of the rat TGB gene will be 150 Kb, which makes this gene the largest so far identified eukaryotic gene. We propose in addition that the 3' end exons arose by duplication of a common ancestor.     

Structural organization of the rat gene for the arginine vasopressin-neurophysin precursor.

The rat arginine vasopressin-neurophysin precursor gene has been isolated from a genomic library cloned in lambda phage Charon 4A. Restriction mapping and nucleotide sequence analysis demonstrated that the gene is 1.85 kilobase pairs long and contains two intervening sequences located in the protein coding region. Exon A encodes a putative signal peptide, the hormone arginine vasopressin and the variable N terminus of the carrier protein neurophysin, exon B encodes the highly conserved middle part of neurophysin and exon C its variable C terminus together with glycoprotein. Thus, the three functional domains of the percursor - arginine, vasopressin, neurophysin, glycoprotein - are encoded on three distinct exons.     

Expression of ceruloplasmin gene in various organs of the rat

The contribution of different rat organs to the synthesis of ceruloplasmin (Cp) was studied. Dot hybridization with the use of the Cp cDNA probe revealed Cp mRNA sequences in RNA preparations from liver, heart, kidney as well as from different divisions of brain, the concentration of Cp mRNA sequences being maximal in the liver. Polyribosomes isolated from these organs effectively synthesized Cp in a cell-free system derived from rabbit reticulocytes. After in vivo pulse labeling, the newly formed radioactive Cp was detected in the membrane fractions from all these organs. The newly formed Cp was concentrated within the membranes of the Golgi complex of various organs where it was revealed by different immunochemical techniques. Experiments with isolation of the liver from the systemic circulation showed that the liver is the only organ secreting Cp into the blood stream. It was suggested that mammalian tissues contain at least two molecular forms of Cp, i. e., circulatory and intracellular ones.     

Structural organization of multiple rat calmodulin genes

Elsewhere, we have reported the structure of a rat calmodulin gene and two distinct rat calmodulin cDNAs, pRCM1 and pRCM3. Here, I report the cloning and sequencing of the third calmodulin cDNA (pRCM4) and two additional rat calmodulin genes. The original calmodulin gene is named CaM I (pRCM1) and the newly discovered calmodulin genes are named CaM II (pRCM3) and CaM III (pRCM4). CaM II spans about 10 x 10(3) base-pairs and consisted of five exons, while CaM III spans about 7.2 x 10(3) base-pairs and consisted of six exons. One of the introns (intron 3) observed in CaM I and CaM III is lost in CaM II. Otherwise, the intron/exon organization of these genes is exactly the same. In all calmodulin genes, the first intron separates the initiation codon (ATG) from the coding region of the protein. Northern blotting showed that CaM I is transcribed primarily into 1.7 x 10(3) base-pair mRNA in various tissues examined and 4.0 x 10(3) base-pair mRNA mainly in skeletal muscle, CaM II is transcribed into 1.4 x 10(3) base-pair mRNA almost exclusively in brain and CaM III is transcribed predominantly into 2.3 x 10(3) base-pair mRNA and faintly into 1.0 x 10(3) base-pair mRNA mainly in skeletal muscle and brain. DNA sequences in the promoter-regulator regions of these genes are partly homologous but essentially distinct and possess a number of direct repeats, palindromes and feasible stem-loop structures. Together with these, I report here the structures of the third and fourth calmodulin retropseudogenes.     

Structural organization of the mouse lactoferrin gene.

The complete structure of the mouse lactoferrin gene is presented. Mouse lactoferrin (mLF) is encoded by a single copy gene of approximately 30 kilobases (kb) in size. The gene is organized into 17 exons separated by 16 introns. The exons range in size from 48 base pairs (bp) to 190 bp whereas the introns range from 0.2 kb to 4.3 kb. Structural analysis of the mouse lactoferrin gene reveals that this gene shares a similar intron-exon distribution pattern with both human transferrin and chicken ovotransferrin.     

Structural organization of amygdaloid brain complex of the rat

Amygdala belong to the system of basal nuclei of telencephalon. Amygdala are a complicated structure based on both principles of grey matter organization: nuclear and screen-type, on its territory. Authors investigate into the structure of Amygdala using theory of Zavarzin A. As the result of this study, a classification of components of Amygdala into nuclei, paleocortical and intermediate formations, has been developed.