No description available.

The nucleotide sequence of cnjB, a conjugation specific gene of Tetrahymena thermophila, has been determined. The gene encodes a putative polypeptide (CnjB) of 1748 amino acids with a calculated molecular weight of 200 kilodaltons and a pI of 7.9. Four transcription start sites were mapped. The gene has only one genomic copy and is not conserved in yeast (as determined by cross-hybridization experiments with yeast DNA). Analysis of the 13 introns in cnjB, accompanied by 15 other T. thermophila intron sequences, shows that they resemble the nuclear pre-mRNA introns of other eukaryotes. / The carboxy-terminal third of CnjB has three regions with repetitive sequences. One region contains seven retroviral-type zinc fingers and the others contain repeated glycine-rich motifs, a motif seen in the heterogeneous nuclear ribonuclear proteins A1 and A2/B1. Proteins with these motifs have single-strand binding and strand annealing activity. / Synthetic phosphorothioate oligonucleotides antisense to regions of the isoleucyl tRNA synthetase gene transcript did not affect cell growth in a sequence-specific manner when cultures of T. thermophila were grown in their presence.

The nucleotide sequence of the cnjA cDNA (formerly pC1) from the ciliated protozoan Tetrahymena thermophila was determined. This gene was previously found to be conjugation specific and to peak in expression just prior to or at pachytene in meiotic prophase I. The cnjA message is initiated from four transcription start sites, one minor and three major, and encodes a putative protein (CnjA) of 779 amino acids. The protein has a calculated molecular weight of 89.5 kDa and is mainly hydrophilic with an estimated pI of 9.3. CnjA was found to share no sequence similarities with any known protein to date. The gene's coding region demonstrates an unusual codon choice. Flanking regions of the cnjA genomic locus were amplified by means of the Inverse PCR method but attempts at subcloning and characterizing its promoter region were unsuccessful.

No description available.

Isoleucyl-tRNA synthetase genes from the yeast Saccharomyces cerevisiae and the ciliated protozoan Tetrahymena thermophila were sequenced. The intronless S. cerevisiae gene (ILS1) encodes a putative polypeptide of 1072 amino acids. Two putative promoter elements were identified, one for general amino acid control and one for constitutive transcription. A heat shock protein gene lies upstream of ILS1. The T. thermophila isoleucyl-tRNA synthetase gene (ilsA: formerly cupC) has eight introns, four transcription start sites, and codes for a putative polypeptide of 1081 amino acids with two leucine-zippers. These eukaryotic isoleucyl-tRNA synthetases are 47% identical. They are compared to homologous enzymes from Escherichia coli and an archaebacterium, and to other aminoacyl-tRNA synthetases. / Intron sequences and junctions from T. thermophila and other eukaryotes were analyzed and all but yeast and mammalian introns were found to be A + T enriched. T. thermophila transcription start sites were analyzed and occur at a T or an A within the consensus sequence (A/T)$ sb{ rm n}$ T A A (A)$ sb{ rm n}.$

No description available.