Isolation and complete nucleotide sequence of the gene for bovine parathyroid hormone

The structure of the bovine parathyroid hormone (PTH) gene has been analyzed by Southern blot hybridization of genomic DNA and by nucleotide sequence analysis of a cloned PTH gene. In the Southern analysis, several restriction enzymes produced single fragments that hybridized to PTH cDNA suggesting that there is a single bovine PTH gene. The restriction map of the cloned gene is the same as that determined by Southern blot analysis of bovine DNA. The sequence of 3154 bp of the cloned gene has been determined including 510 bp and 139 bp in the 5' and 3' flanking regions, respectively. The gene contains two introns which separate three exons that code primarily for: (i) the 5' untranslated region, (ii) the pre-sequence of preProPTH, and (iii) PTH and the 3' untranslated region. The gene contains 68% A + T and unusually long stretches of 100- to 150-bp sequences containing alternating A and T nucleotides in the 5' flanking region and intron A. The 5' flanking region contains two TATA sequences, both of which appear to be functional as determined by S1 nuclease mapping. Compared to the rat and human genes, the locations of the introns are identical but the sizes differ. Comparable human and bovine sequences in the flanking regions and introns are about 80% homologous.     

Analysis of the regions flanking the human insulin gene and sequence of an Alu family member.

The regions around the human insulin gene have been studied by heteroduplex, hybridization and sequence analysis. These studies indicated that there is a region of heterogeneous length located approximately 700 bp before the 5' end of the gene; and that the 19 kb of cloned DNA which includes the 1430 bp insulin gene as well as 5650 bp before and 11,500 bp after the gene is single copy sequence except for 500 bp located 6000 bp from the 3' end of the gene. This 500 bp segment contains a member of the Alu family of dispersed middle repetitive sequences as well as another less highly repeated homopolymeric segment. The sequence of this region was determined. This Alu repeat is bordered by 19 bp direct repeats and also contains an 83 bp sequence which is present twice. The regions flanking the human and rat I insulin genes were compared by heteroduplex analysis to localize homologous sequences in the flanking regions which could be involved in the regulation of insulin biosynthesis. The homology between the two genes is restricted to the region encoding preproinsulin and a short region of approximately 60 bp flanking the 5' side of the genes.     

Molecular cloning of cDNA of S100 alpha subunit mRNA

The primary structure of the bovine S-100 alpha mRNA on the basis of molecular cloning and sequence analysis of the cDNA are described. The sequence is composed of 532 bp which include the 282 bp of the complete coding region, 89 bp at the 5'-noncoding region, 161 bp at the 3'-noncoding region, polyadenylation signal, ATTAAA and poly(A) tail. Northern blot analysis shows that the size of S-100 alpha mRNA is about 700-800 bases long and a single mRNA occurs in bovine brain. Bovine brain contains both S100 alpha and beta subunits and their mRNAs. In contrast, the rat brain contains only S100 beta subunit and its mRNA.     

A leucine tRNA gene adjacent to the QA gene cluster of Neurospora crassa.

A single tRNALeu gene has been localized and sequenced from Neurospora crassa. It is located only 375 bp from the qa gene cluster and it is the only tRNA or 5S rRNA gene within this cloned 37 kb region. The gene encodes a tRNALeu with the anti-codon AAG, and unlike the other nuclear eukaryotic tRNALeu (AAG) gene sequenced (from C. elegans), contains an intervening sequence of 27 bp. The Neurospora tRNALeu (AAG) is 84% and 73% homologous respectively to the C. elegans and bovine tRNALeu (AAG), and is 84% homologous to a Drosophila tRNALeu (CAA). However, it is only 65% homologous to a yeast tRNALeu (CAA) and there is little conservation of intervening sequences or V-loop regions. The gene hybridizes to at least 16 other DNA fragments in the Neurospora genome. Its expression does not seem to be linked to that of the qa genes.     

Isolation and characterisation of genes for androgen-responsive secretory proteins of rat seminal vesicles.

Under the influence of testosterone, rat seminal vesicles synthesise large amounts of a tissue specific protein, S. Recombinant lambda clones have been isolated containing overlapping sequences covering a 27.5 kilo base region of the rat genome within which the gene for protein S is located. Recombinant plasmids bearing cDNA sequences for protein S were constructed in pBR328. One (pcS2) contains a 690 nucleotide insert and is probably full length. Detailed restriction maps of the S-gene are presented and the structure was confirmed by analysis of R-loops and heteroduplexes. The S-gene covers a 2 kbp region of the genome and consists of a 5' intron (490 bp) separating a leading exon (120 bp) containing the 5' untranslated region from a central exon (310 bp) containing most of the coding sequence and part of the 3' untranslated region. A larger intron (1100 bp) lies within the 3' untranslated region. The cloned gene is representative of the native gene but the S gene may be heterogeneous. Using pcS2, the hormonal control of S-specific mRNA was examined and a pronounced differential response to testosterone was observed.     

Zea mays chloroplast ribosomal RNA genes are part of a 22,000 base pair inverted repeat

Zea mays chloroplast rDNA exists in two identical units. Each unit contains one sequence for the 16, 23 and 5S rRNAs in the order given. The 16 and 23S sequences in each unit are separated by a 2100 base pair (bp) spacer. The DNA sequence for 5S RNA is closely linked to that for the 23S RNA. Within the above unit, the three RNAs are transcribed from a single DNA strand. The two rDNA units on the circular chloroplast DNA molecule are separated from each other by 18,500 bp in one direction and by 106,100 bp in the other direction. The two rDNA units have an inverted orientation with respect to each other. Each rDNA unit is part of a 22,000 bp sequence which is repeated with inverted orientation.     

Rat prostatic binding protein: the complete sequence of the C2 gene and its flanking regions.

The complete sequence (2879 bp) of the androgen-controlled rat prostatic binding protein C2 gene and 1023 bp of the 5'- and 2127 bp of the 3'-flanking regions have been determined. The gene contains three exons (93, 203 and 147 bp) and two introns (1630 and 806 bp). It is flanked by two homopurine-homopyrimidine stretches of 55 and 131 nucleotides respectively, located at positions -405 and 4151. These sequences are remarkably sensitive towards S1-nuclease, indicating an altered DNA conformation under superhelical stress. Several palindromes and dyad structures are observed in the 5'-upstream region of the gene and at position -457, and 80% homology to the consensus sequence of a glucocorticoid receptor binding site is found.     

The genes for the ribosomal proteins S12 and S7 are clustered with the gene for the EF-Tu protein on the chloroplast genome of Euglena gracilis.

We characterize a DNA segment of the Euglena gracilis chloroplast DNA fragment Eco . N by nucleotide sequencing and S1 nuclease analysis. We show that this region, which is upstream of the previously sequenced tuf A gene, contains the genes for the ribosomal proteins S12 and S7. The gene arrangement is 5'-rps 12-80 bp spacer-rps 7-174 bp spacer-tuf A, somewhat similar to the str operon of E. coli. The chloroplast S12 and S7 proteins contain 124 and 155 aminoacids, respectively, and are to 68% and 38% homologous with the corresponding E. coli proteins. The region is transcribed into a distronic mRNA of about 1.1 to 1.2 kb. The rps 12 and rps 7 genes, contrary to the tuf A gene, are not split.     

Complete sequence of Euglena gracilis chloroplast DNA.

We report the complete DNA sequence of the Euglena gracilis, Pringsheim strain Z chloroplast genome. This circular DNA is 143,170 bp, counting only one copy of a 54 bp tandem repeat sequence that is present in variable copy number within a single culture. The overall organization of the genome involves a tandem array of three complete and one partial ribosomal RNA operons, and a large single copy region. There are genes for the 16S, 5S, and 23S rRNAs of the 70S chloroplast ribosomes, 27 different tRNA species, 21 ribosomal proteins plus the gene for elongation factor EF-Tu, three RNA polymerase subunits, and 27 known photosynthesis-related polypeptides. Several putative genes of unknown function have also been identified, including five within large introns, and five with amino acid sequence similarity to genes in other organisms. This genome contains at least 149 introns. There are 72 individual group II introns, 46 individual group III introns, 10 group II introns and 18 group III introns that are components of twintrons (introns-within-introns), and three additional introns suspected to be twintrons composed of multiple group II and/or group III introns, but not yet characterized. At least 54,804 bp, or 38.3% of the total DNA content is represented by introns.     

Sequence heterogeneity in the internal transcribed spacers of two rat ribosomal DNA clones

The sequence of one cloned rat rDNA segment is determined, encompassing the 3'-terminal part of 18 S rDNA (231 bp), ITS 1 (1072 bp), 5.8 S rDNA (156 bp), ITS 2 (771 bp) and the 5'-terminal part of 28 S rDNA (210 bp). Comparison with a distinct clone of the same rDNA segment reveals the identity of the rRNA gene sequences and considerable heterogeneity in both ITS 1 and ITS 2. The heterogeneities include mainly single base-pair changes (23 deletions or insertions and 14 substitutions) distributed all along the ITS sequences.