Cortese R et al. (1978) Nucleic Acids Res "Cloning of nematode tRNA genes and their expression in the frog oocyte."

Tranquilla TA, Smith JD, Cortese R, Melton DA

[Nucleic Acids Res, 1978]

Transfer RNA genes of the nematode Caenorhabditis elegans have been cloned in E. coli using the plasmid Col E1 as vector. The tRNAs coded by 3 hybrid plasmids were purified by hybridisation of labelled nematode tRNA with the plasmid DNAs. Each plasmid appears to code for a single distinct tRNA species. The expression of the cloned DNAs was analysed in vivo by injection into nuclei of Xenopus laevis oocytes. Evidence is presented which suggests that these nematode tRNA genes are accurately transcribed and processed in frog oocytes. Analysis of one hybrid plasmid shows that a 300 base pair DNA fragment contains both the structural gene and those regions required for its transcription in vivo. The results show that cloned eukaryotic DNAs from a heterologous source can be tested for functional gene activity in X. laevis oocytes.

Melton DA et al. (1979) Cell "Transcription of cloned tRNA genes and the nuclear partitioning of a tRNA precursor."

Cortese R, Melton DA

[Cell, 1979]

The transcription of transfer RNA genes (tDNAs) and processing of the transcripts have been studied by injecting cloned tDNAs into Xenopus oocyte nuclei. Three main conclusions can be drawn. First, eucaryotic nuclear tRNA genes, but neither procaryotic nor mitochondrial tRNA genes, are expressed in injected oocytes. While both nematode and yeast tDNAs direct the synthesis of authentic tRNAs, neither E. coli tDNA nor human mitochondrial tDNAs support the synthesis of defined tRNAs when injected into oocytes. Second, competition experiments with co-injected 5S genes and inhibition experiments with a-amanitin show that injected tDNAs are transcribed by RNA polymerase III. Third, oocytes injected with a nematode tDNA synthesize a tRNA precursor which is processed post-transcriptionally by removal of a 5' leader sequence. This precursor is found exclusively in the nucleus and is processed in the nucleus before the mature tRNA enters the cytoplasm.

Traboni C et al. (1984) Cell "Mutations in Box B of the promoter of a eucaryotic tRNAPro gene affect rate of transcription, processing, and stability of the transcripts."

Ciliberto G, Traboni C, Cortese R

[Cell, 1984]

We have constructed a series of single and double base-pair-substitution mutants in and around the second component (Box B) of the promoter of a tRNA(Pro) gene from C. elegans. Their analysis in in vivo and in vitro transcriptional systems establishes the importance of single nucleotides in the promotion of transcription. Most mutants in the region coding for the T*CG stem-loop show a reduced gene expression associated with lack of processing of the primary transcriptional products; in the oocytes these are rapidly degraded, with a half-life considerably shorter than that of wild-type tRNA molecules. In contrast, mutations in the DNA region coding for anticodon stem-loop do not alter the efficiency of transcription or the processing of the transcripts.

Ciliberto G et al. (1982) Proc Natl Acad Sci U S A "Relationship between the two components of the split promoter of eukaryotic tRNA genes."

Traboni C, Ciliberto G, Cortese R

[Proc Natl Acad Sci U S A, 1982]

Plasmids containing eukaryotic tRNA genes are faithfully transcribed in the nucleus of Xenopus laevis oocytes. It has been established that two separated regions within the coding sequence of a tRNA gene are essential and sufficient for the promotion of transcription. We have constructed a hybrid tRNA gene containing one essential region from tDNA*Leu and the other from tDNA*Pro, both from Caenorhabditis elegans. This hybrid gene is efficiently transcribed, thus showing that the essential regions are independent transcriptional signals regardless of overall regularities of the structure of tRNA genes. We have also constructed mutants of the tRNA*Pro gene in which the distance between the two essential regions is changed; optimal transcription occurs when this distance is about 40-50 nucleotides.

Traboni C et al. (1982) EMBO J "A novel method for site-directed mutagenesis: its application to an eukaryotic tRNAPro gene promoter."

Cortese R, Traboni C, Ciliberto G

[EMBO J, 1982]

We present a novel general method for localized mutagenesis. The DNA segment to be mutagenized is inserted in the B-galactosidase gene of a M13-lac vector, generally causing loss of B-galactosidase function by generation of frameshift or nonsense codons. Mutations in the inserted DNA which restore B-galactosidase function are readily detected and analyzed. The application of this method to the promoter of an eukaryotic (Caenorhabditis elegans) tRNA*Pro gene has allowed the isolation of several mutants altered in transcription.

Ciliberto G et al. (1982) Proc Natl Acad Sci U S A "Promoter of a eukaryotic tRNAPro gene is composed of tree noncontiguous regions."

Ciliberto G, Melton DA, Cortese R, Castagnoli L

[Proc Natl Acad Sci U S A, 1982]

The 71-base-pair coding sequences of the tRNAPro gene from Caenorhabditis elegans contains all of the information required for transcription and processing in the injected oocytes. Several subclones of the DNA coding for the tRNAPro were constructed, carrying deletions or insertions, or both. Their transcriptional properties lead to the hypothesis that the tRNAPro gene promoter is composed of three discontinuous regions within the coding sequence.

Tranquilla TA et al. (1982) Nucleic Acids Res "Sequences of four tRNA genes from Caenorhabditis elegans and the expression of C. elegans tRNALeu (anticodon IAG) in Xenopus oocytes."

Tranquilla TA, Cortese R, Smith JD, Melton DA

[Nucleic Acids Res, 1982]

Four tRNA genes have been identified in cloned segments of Caenorhabditis elegans DNA by tRNA hybridisation and expression after injection into Xenopus laevis oocyte nuclei. From DNA sequencing these are (with DNA anticodon sequences) tRNAAsp (GTC), tRNALeu (AAG), tRNALys (CTT) and tRNAPro (TGG). Their flanking DNA sequences are compared. Two identical tRNALys (CTT) genes from different regions of the genome have quite unrelated 5' flanking sequences. The tRNA synthesised in Xenopus oocytes after injection of the tRNALeu cloned DNA has the modified anticodon IAG. The tRNALeu gene precursor transcript from injected oocytes has short 5' and 3' additional sequences and lacks certain of those modified bases found in the processed tRNA.

Galindo-Malagn XA et al. (2022) Zootaxa "New species, synonymies and records in the genus Rhagovelia Mayr, 1865 (Hemiptera: Heteroptera: Veliidae) from Colombia."

Moreira FFF, Morales I, Mondragn-F SP, Galindo-Malagn XA

[Zootaxa, 2022]

Rhagovelia medinae sp. nov., of the hambletoni group (angustipes complex), and R. utria sp. nov., of the hirtipes group (robusta complex), are described, illustrated, and compared with similar congeners. Based on the examination of type specimens, six new synonymies are proposed: R. elegans Uhler, 1894 = R. pediformis Padilla-Gil, 2010, syn. nov.; R. cauca Polhemus, 1997 = R. azulita Padilla-Gil, 2009, syn. nov., R. huila Padilla-Gil, 2009, syn. nov., R. oporapa Padilla-Gil, 2009, syn. nov, R. quilichaensis Padilla-Gil, 2011, syn. nov.; and R. gaigei, Drake Hussey, 1947 = R. victoria Padilla-Gil, 2012 syn. nov. The first record from Colombia is presented for R. trailii (White, 1879), and the distributions of the following species are extended in the country: R. cali Polhemus, 1997, R. castanea Gould, 1931, R. cauca Polhemus, 1997, R. gaigei Drake Hussey, 1957, R. elegans Uhler, 1894, R. femoralis Champion, 1898, R. malkini Polhemus, 1997, R. perija Polhemus, 1997, R. sinuata Gould, 1931, R. venezuelana Polhemus, 1997, R. williamsi Gould, 1931, and R. zeteki Drake, 1953.

Tranquilla TA et al. (1979) International C. elegans Meeting "cloning and characterization of nematode mRNA."

Melton DA, Tranquilla TA, Smith JD, Cortese R

[International C. elegans Meeting, 1979]

Dente L et al. (1982) EMBO J "A prokaryotic tRNATyr gene, inactive in Xenopus laevis oocytes, is activated by recombination with an eukaryotic tRNAPro gene."

Fasano O, Traboni C, Cortese R, Dente L, Costanzo F, Ciliberto G

[EMBO J, 1982]

Eukaryotic tDNA promoters are composed of two essential regions contained within the coding sequence (Box A and Box B). Due to the highly conserved structure of prokaryotic and eukaryotic tRNA, most prokaryotic tRNA genes are expected to be active templates in eukaryotic transcriptional systems. In this paper we show that Escherichia coli tDNA Tyr is not transcribed in the nucleus of Xenopus laevis oocytes. By in vitro construction of hybrid molecules between inactive prokaryotic tDNA Tyr from E. coli, and active eukaryotic tDNA Pro from Caenorhabditis elegans, we show that tDNA Tyr can be made into an active gene if its first third, including the Box A region, is replaced by that of the eukaryotic tDNA. These results suggest that an improper Box A sequence is responsible for the inactivity of the E. coli tRNA Tyr gene, and argue against the role of secondary and tertiary DNA conformations in RNA polymerase III transcription.