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Cloning and sequencing of the 3'-region of the canine parathyroid hormone-related protein gene and analysis of alternate mRNA splicing in two canine carcinomas.

A canine genomic library in Lambda FIX II vector was screened with a 281-base pair canine PTHrP cDNA to the prepro- and coding regions. Two genomic clones were isolated and mapped to the 3'-end of the PTHrP gene by polymerase chain reaction (PCR) amplification of exons in this region. One clone (3.5 kb) was amplified by PCR, partially sequenced, and compared to the human PTHrP gene. Regions were identified with a high degree of homology to exons 6, 7, and 8 of the human PTHrP gene. A polyadenylation site was present 3' to the exon 8-like region. Reverse transcriptase-polymerase chain reaction (RT-PCR) demonstrated that exon 7 of the PTHrP gene was transcribed in two canine carcinomas (SCC 2/88 cells and CAC-8 tumor line) which produce PTHrP. This confirmed that the 3'-region of the canine PTHrP gene is alternately spliced with splicing of exon 6 to exons 7 or 9. Transcription of exon 8 was not demonstrated by RT-PCR and suggests that the exon 8-like region of the dog PTHrP gene is not utilized. The exon 8-like region contained an early stop codon that was not present in exon 8 of the human PTHrP gene.

Adenocarcinoma↗

A developmental bias in reading frame usage by human fetal thymic TCRBDJ transcripts is not present in genomic TCRBDJ rearrangements.

We have previously reported that reading-frame usage and functional diversification is developmentally regulated, with virtually all TCRB DJ mRNA transcripts using a single reading frame at 8 weeks of gestational age, tapering to 50% by adult life. We used the polymerase chain reaction to create genomic libraries of DJ rearrangements in the TCRB locus from thymuses at 7.7, 10, and 16 weeks of gestational age, and from adult thymuses. Clones were randomly picked and sequenced to determine junctional sequences and reading-frame utilization. The resulting data address the hypothesis that cells bearing genomic joints in reading frame one are preferentially selected during fetal life. This hypothesis predicts that reading-frame bias would also be observed among genomic DJ joints. Instead, we observed random utilization of the three possible D-region reading frames among genomic D1s1 ==> J1s1 joints during fetal life. Similar results were obtained at 7.7 weeks of gestational age in a second thymus in which both RNA and DNA were simultaneously isolated and used to create libraries of TCRBDJ transcripts or rearrangements. We conclude that reading-frame utilization is random among genomic D1s1-JB1s1 rearrangements and that the preferential usage of a single reading frame among mRNA transcripts of TCRB DJ transcripts is the result of preferential transcription of genomic TCRB DJ joints in a single reading frame, or that TCRB DJ transcripts have a longer half-life than transcripts in reading frames two or three.

Embryonic and Fetal Development↗

A DNA probe specific to pathogenic Entamoeba histolytica.

A DNA sequence, IE-gen1 (3.1 kb), was isolated from the pathogenic strain of E. histolytica NIH-200. IE-gen1 was identified by the subtractive hybridization of a genomic library to a cDNA probe prepared from NIH-200 trophozoites. The IE-gen1 probe specifically detected pathogenic E. histolytica in slot blots of genomic DNA and Northern blots, but not other Entamoeba species and additional human parasites. This genomic probe could detect with complete specificity DNA from about 10(3) organisms. The IE-gen1 probe could be related to highly specialized loci in pathogenic E. histolytica, and is likely to be a valuable DNA reagent for clinical diagnosis and epidemiological investigations.

Animals↗

Isoproterenol response following transfection of the mouse beta 2-adrenergic receptor gene into Y1 cells.

The beta 2-adrenergic receptor (beta 2AR) gene was isolated from a mouse genomic library, sequenced and shown to share 93% identity with the hamster beta 2AR cDNA at the amino acid level. This mouse beta 2AR genomic clone was transfected into the Y1 mouse adrenal cortex tumor cell line. Northern blot and S1 nuclease analysis showed that the beta 2AR-transfected cells expressed an mRNA of the appropriate size to encode the receptor. Membrane receptor number and affinities for various beta-adrenergic agonists demonstrated that the transfected clone encoded a beta 2AR protein product. Incubation of the transfected Y1 cells, which do not normally possess beta 2AR, with the beta 2AR agonist, isoproterenol, resulted in an increase in the rate of steroid secretion by these cells as well as a rapid change in cell morphology. This response was fully blocked by the beta 2AR antagonist, propranolol. Prolonged incubation of the cells with isoproterenol resulted in agonist insensitivity and an 80% reduction in membrane receptor number.

Amino Acid Sequence↗

Cloning of the murine eosinophil peroxidase gene (mEPO): characterization of a conserved subgroup of mammalian hematopoietic peroxidases.

The mouse eosinophil peroxidase (mEPO) gene was cloned by screening a random-primed bone marrow cDNA library at reduced criteria using a hEPO cDNA. An mEPO cDNA was subsequently used to isolate the mEPO gene from a lambda-genomic library. The mEPO gene displays a high degree of conservation with its human homologue: the transcription units are approximately the same size, conserve the relative size and position of the 12 exons associated with each gene, and at a nucleotide level the mouse and human EPO genes are 86% identical in the protein coding regions and 66% identical in the 3'-untranslated trailer regions. This strong conservation extends to the encoded proteins which show approximately 90% amino acid identity. Expression of the mEPO gene is restricted to tissues containing eosinophil progenitor cells (e.g., bone marrow and spleen), a pattern similar to the expression of another murine eosinophil granule protein, major basic protein.

Amino Acid Sequence↗

Development of a new transformant selection system for Penicillium chrysogenum: isolation and characterization of the P. chrysogenum acetyl-coenzyme A synthetase gene (facA) and its use as a homologous selection marker.

A new transformation system for the filamentous fungus Penicillium chrysogenum is described, based on the use of the homologous acetyl-coenzyme A synthetase (facA) gene as a selection marker. Acetate-non-utilizing (Fac-) strains of P. chrysogenum were obtained by positive selection for spontaneous resistance to fluoroacetate. Among these fac mutants putative facA strains were selected for a loss of acetyl-coenzyme A (CoA) synthetase activity. The facA gene, coding for the enzyme acetyl-CoA synthetase, was isolated from a P. chrysogenum genomic library using synthetic oligonucleotides derived from conserved regions from the corresponding genes of Aspergillus nidulans and Neurospora crassa. Vector pPC2-3, comprising a genomic 6.5 kb PstI fragment, was able to complement P. chrysogenum facA strains with frequencies up to 27 transformants.micrograms-1 DNA. Direct selection of transformants was accomplished using acetate and low amounts (0.001%) of glucose as carbon sources. About 50% of the transformants arose by integration of pPC2-3 DNA at the homologous facA locus and 50% by integration elsewhere in the genome. Determination of the nucleotide sequence of part of the cloned fragment showed the presence of an open reading frame of 2007 nucleotides, interrupted by five putative introns. Comparison of the nucleotide and the amino acid sequence of the facA gene of P. chrysogenum with the facA gene of A. nidulans reveals similarities of 80% and 89%, respectively. The putative introns present in the P. chrysogenum facA gene appear at identical positions as those in the A. nidulans facA gene, but show no significant sequence similarity.

Acetate-CoA Ligase↗

A rat histone H4 gene closely associated with the testis-specific H1t gene.

A rat histone H4 gene closely associated with the testis-specific H1t gene was isolated by screening the Sargent-Bonner rat genomic library using cloned human histone genes as probes. Both the H4 gene and the H1t gene are located on a 7-kb EcoRI genomic DNA fragment. Although the deduced amino acid sequence of the rat H4 histone is identical to that of the sequence of human histone H4, the nucleotide sequence of the coding region differs significantly from the coding region of the human H4 gene. Moreover, the relative spacing between the 5'-consensus sequence elements is unique for an H4 gene. S1-nuclease protection analyses reveal that both the H4 and H1t mRNA species are present in a fraction of rat testis cells highly enriched in pachytene spermatocytes, while only the H4 mRNA species is present in a rat myeloma cell line (Y3-Ag1.2.3). During a 1-h hydroxyurea treatment of the Y3 cells, which produces a 99% inhibition of DNA synthesis, the level of this H4 mRNA drops by only 50%, indicating that the stability of this mRNA is only partially coupled with DNA synthesis.

Amino Acid Sequence↗

Identification and cloning of genes encoding viomycin biosynthesis from Streptomyces vinaceus and evidence for involvement of a rare oxygenase.

The tuberactinomycins are a family of basic cyclic peptides that exhibit potent antitubercular activity. These peptides are characterized by the presence of an amino acid with a 6-membered cyclic guanidine side chain (capreomycidine) and two or more 2,3-diaminopropionate residues. Viomycin (tuberactinomycin B) is a well-studied member of the family, was once prescribed for the treatment of tuberculosis, and has been shown to block translocation during protein biosynthesis. The gene cluster encoding viomycin biosynthesis was identified and cloned from Streptomyces vinaceus. The cluster was identified by screening genomic libraries with the viomycin phosphotransferase self-resistance gene (vph) and non-ribosomal peptide synthetase (NRPS) gene probes amplified from S. vinaceus genomic DNA. The viomycin cluster was localized to ca. 120 kb of contiguous DNA defined by four overlapping cosmid inserts. Each cosmid hybridized with one or more peptide synthetase gene probes and two also hybridized with vph. Confirmation that the cluster encoded viomycin biosynthesis was obtained from the disruption of two NRPS adenylation domains. Partial sequence analysis revealed an ORF (svox) predicted to encode a rare non-heme iron, alpha-ketoglutarate dependent oxygenase proposed to function in the oxidative cyclization of arginine to the capreomycidine residue. Insertional disruption of svox resulted in complete loss of viomycin production, confirming its involvement in the pathway.

Amino Acid Sequence↗

Genomic structure of the human retinoblastoma-related Rb2/p130 gene.

The human Rb2/p130 gene shares many structural and functional features with the retinoblastoma gene and the retinoblastoma-related p107 gene. In the present study, we have cloned and partially sequenced the gene coding for the Rb2/p130 protein from human genomic libraries. The complete intron-exon organization of this gene has been elucidated. The gene contains 22 exons spanning over 50 kb of genomic DNA. The length of individual exons ranges from 65 to 1517 bp. The largest intron spans over 9 kb, and the smallest has only 82 bp. The 5' flanking region revealed a structural organization characteristic of promoters of "housekeeping" and growth control-related genes. A typical TATA or CAAT box is not present, but there are several GC boxes and potential binding sites for numerous transcription factors. This study provides the molecular basis for understanding the transcriptional control of the Rb2/p130 gene and for implementing a comprehensive Rb2/p130 mutation screen using genomic DNA as a template.

Amino Acid Sequence↗

Organization of a human UDP-GalNAc:polypeptide, N-acetylgalactosaminyltransferase gene and a related processed pseudogene.

We have previously characterized a cDNA that encodes a full length human UDP-GalNAc:polypeptide, N-acetylgalactosaminyltransferase (GalNAc-transferase) (J.A. Meurer et al., J. Biochem., 118, 568-574, 1995). The present report describes the characterization of the corresponding human GalNAc-transferase gene and a related pseudogene. Two human genomic libraries, lambda and P1, were screened with probes derived from the human GalNAc-transferase nucleotide sequence, resulting in the isolation of four genomic clones. Southern blotting, PCR analysis, and sequencing revealed that three clones, lambda.HG-5, P1.GALN-A, and P1.GALN-B, contained overlapping genomic sequences that encompass over 55 kilobase pairs (kb) of genomic DNA and comprise a portion of the human GalNAc-transferase 5'-and 3'-untranslated regions and the entire coding region. The human GalNAc-transferase gene structure consists of at least 11 exons ranging in size from 99 to > 620 nucleotides which are separated by 10 introns ranging in size from 0.7 to approximately 12.5 kb. The fourth genomic clone, P1-GALN-psi, contained a approximately 2.4 kb sequence region which shares an overall 78.6% nucleotide identity with coding region exons 1 and 3 through 11 of the human GalNAc-transferase gene. However, a lack of intron sequences, as well as the presence of multiple nucleotide mutations, insertions, and deletions that disrupt the potential GalNAc-transferase reading frame, suggest that P1.GALN-psi contains a processed pseudogene. Screening of a human/rodent somatic cell hybrid panel with a P1.GALN-psi probe localized the GalNAc-transferase pseudogene to chromosome 3. Hence, the human genome contains at least two related GalNAc-transferase genes that are located on separate chromosomes.

Base Sequence↗

Isolation and characterization of cloned rat DNA fragment carrying tRNA genes.

A rat genomic library was screened for tRNA genes with an unfractionated rat liver tRNA probe. About 70 clones containing tRNA genes were detected per rat genome. The organization of tRNA genes in five clones was analyzed by restriction endonuclease digestion, RNA-DNA hybridization and in vitro transcription with nuclear extracts from Xenopus oocytes. Evidence is presented suggesting that tRNA genes are distributed in the rat genome in small clusters spanning 1 to 2 kb and interspersed with large regions (minimum 8 to 20 kb) of non tRNA-coding DNA. The tRNA gene clusters were found to contain the sequences for a variety of tRNA species. Genes for a single isoacceptor, were found in more than one clone. The detailed study of one clone shows the repetition of a cluster of four tRNA sequences at a distance of about 8 kb. The arrangement of tRNA genes in rat appears to follow the irregular pattern of tRNA gene organization previously reported in Drosophila and Xenopus.

Animals↗

OARE-1, a Ty1-copia retrotransposon in oat activated by abiotic and biotic stresses.

Transcriptionally active Ty1-copia LTR-retrotransposons were found in oat using RT-PCR for amplifying the reverse transcriptase domain. Sequence analysis of the RT-PCR clones suggested that oat LTR-retrotransposons consist of at least seven groups, which were tentatively designated as Oatrt1 to Oatrt7. A full length copy of Oatrt1 was isolated from an oat genomic library, and was designated OARE-1. OARE-1 was 8,665 bp long and a member of the BARE-1 subgroup. The oat genome carried it in multiple copies (at least 10,000 copies / a hexaploid genome). The expression of OARE-1 was intensively induced by wounding, UV light, jasmonic acid and salicylic acid, and its pattern was very similar to that of the PAL (phenylalanin ammonia lyase) gene. Furthermore, OARE-1 was highly activated by infection with an incompatible race of the crown rust fungus, Puccinia coronata. These results suggest that OARE-1 is highly sensitive to various abiotic and biotic stimuli leading to plant defense responses.

Amino Acid Sequence↗

Cloning and molecular characterization of a gene encoding a Cryptosporidium parvum putative 20S proteasome beta1-type subunit.

A DNA sequence composed of 1281 nucleotides (nt) consisting of a single open reading frame (ORF) encoding a putative 20S proteasome beta1-type subunit was isolated from clones derived from genomic libraries constructed from the KSU-1 isolate of Cryptosporidium parvum. Southern blot analysis suggested that the sequenced DNA exists in the C. parvum genome as a single copy; transcription was verified through reverse transcription-polymerase chain reaction (RT-PCR) performed on total RNA isolated from C. parvum sporozoites. The predicted protein consists of 210 amino acids (aa), contains characteristic amino acids common to all proteasomal subunits, and shares stronger similarity to the beta1-type subunit of yeast than to other types of beta-subunits.

Adenosine Triphosphatases↗

Sequence of bovine interleukin 7.

We report the cloning and the sequencing of a cDNA coding for the mature bovine interleukin 7 (IL-7). The clone was isolated from a bovine leukemia virus (BLV)-induced B cell-lymphosarcoma cDNA library. The 5' non-coding sequence and the sequence of the signal peptide were obtained from a clone isolated from a bovine genomic library. The entire bovine IL-7 protein is 176 amino acids long and shows 75 and 65% homology to published sequences of human and murine IL-7, respectively.

Amino Acid Sequence↗

The gene and deduced protein sequences of the zymogen of Aspergillus niger acid proteinase A.

Proteinase A obtained from the culture medium of Aspergillus niger var. macrosporus is a unique acid endopeptidase that is insensitive (or less sensitive) to specific inhibitors of ordinary acid or aspartic proteinases, such as pepstatin, diazoacetyl-DL-norleucine methyl ester, and 1,2-epoxy-3-(p-nitrophenoxy)-propane. In the preceding paper (Takahashi, K., Inoue, H., Sakai, K., Kohama, T., Kitahara, S., Takishima, K., Tanji, M., Athauda, S. B. P., Takahashi, T., Akanuma, H., Mamiya, G., Yamasaki, M. J. Biol. Chem. 266, 19480-19483), we reported the complete primary structure of the mature enzyme determined at the protein level. The enzyme has a unique two-chain structure with a 39-residue light (L) chain and a 173-residue heavy (H) chain linked noncovalently. As an extension of this study, we isolated genomic and cDNA clones encoding this proteinase and determined their nucleotide sequences. To isolate a genomic clone, the genomic DNA was selectively amplified by polymerase chain reaction using mixed oligonucleotide primers designed from the amino acid sequence of the H chain, and a specific probe thus generated was used for screening a lambda gt10 genomic library. A cDNA for the enzyme was also selectively amplified by polymerase chain reaction using primers synthesized based on the sequence of the genomic DNA. Sequencing of the cloned genomic DNA and cDNA revealed the nucleotide sequence of the structural gene for the enzyme of 846 base pairs without introns. It encodes the precursor form of proteinase A, including an NH2-terminal preprosequence of 59 residues, the L chain of 39 residues, an intervening sequence of 11 residues, and the H chain of 173 residues linked in that order. Thus, proteinase A is thought to be synthesized as a single peptide chain preproenzyme of 282 residues, which is processed to generate the mature two-chain form.

Amino Acid Sequence↗

The rat fibrinogen genes. Linkage of the A alpha and gamma chain genes.

We have utilized cDNA probes for the alpha, beta, and gamma chains of rat fibrinogen to isolate the corresponding genes from two rat genomic libraries constructed in bacteriophage Charon 4A. There is a single copy of each gene. Mapping of greater than 92 kilobase pairs of rat genomic DNA has shown that the gamma and alpha chain genes are directly linked in a 5'-3' direction in vivo.

Animals↗

Genomic organization and tissue expression of the murine gene encoding the protein beta-aspartate methyltransferase.

Two overlapping clones containing the entire 684-nucleotide (nt) sequence encoding murine protein beta-aspartate methyltransferase (EC 2.1.1.77) were isolated from a genomic library. Partial nt sequence analysis of the two clones revealed that the protein carboxyl methyltransferase (PCMT)-encoding sequence is distributed among seven exons, ranging from 32 to 339 bp in length, within 25 kb of genomic DNA. Three exons correspond to regions of primary structure which are strongly conserved among a number of eukaryotic and prokaryotic enzymes which utilize S-adenosylmethionine (AdoMet) and S-adenosylhomocysteine (AdoHcy). The 5'-flanking region of the PCMT-encoding gene (PCMT) contains an 800-bp G+C-rich region with potential binding sites for transcription factor ETF, but lacks a TATA box and binding sites for other known transcription factors. Multiple PCMT mRNAs were detected on Northern blots of RNA extracted from murine brain, testis, liver and kidney. The overall abundance of PCMT mRNAs in each tissue paralleled the measured specific activity of the PCMT. Comparison of the genomic sequence information with the 3'-untranslated regions (UTRs) of two cDNA clones from a murine testis library indicated that PCMT mRNA precursors undergo alternative splicing. The structure and widespread expression of PCMT are characteristics of vertebrate housekeeping genes.

Amino Acid Sequence↗

Differential induction of a peroxidase gene family during infection of rice by Xanthomonas oryzae pv. oryzae.

Induction of peroxidase has been correlated with resistant interactions between rice and Xanthomonas oryzae pv. oryzae. To assist in analysis of the role of rice peroxidases in plant defense against the bacterial pathogen, three peroxidase genes, POX22.3, POX8.1, and POX5.1, were identified from a rice cDNA library that was constructed from leaves of plants undergoing a resistant reaction. These genes were highly similar in nucleic acid and amino acid sequences and belonged to a gene family. The three genes showed differential expression in infiltrated rice leaves during pathogen interactions and mechanical stress. Only two peroxidase genes, POX8.1 and POX22.3, were predominantly expressed during resistant interactions. These two genes also were expressed during susceptible interactions, but induction was delayed compared with resistant interactions. POXgX9, a fourth peroxidase gene that was isolated from a genomic library, is adjacent to POX22.3 in the rice genome and has greater than 90% similarity in nucleotide and amino acid sequence identity to POX22.3. Interestingly, POXgX9 was expressed only in the roots of rice plants. While POX22.3 was expressed in both leaves and roots, POX8.1 and POX5.1 were not detected in roots but were induced in leaves by mechanical wounding at different times after treatment. POX22.3, POX8.1, and POX5.1 were estimated to be present in single copies in rice haploid genome. These results indicate that different members of the rice peroxidase gene family are distinctly regulated in response to various environmental cues.

Amino Acid Sequence↗