High impact information on TFP1

• An unusual protein splicing reaction joins the N-terminal segment (A) and the C-terminal segment (C) of the 119K primary translation product (ABC) of the yeast VMA1 gene to yield a 69K vacuolar H(+)-ATPase subunit (AC) and an internal 50K polypeptide (B) [1].
• Cleavage at this site only occurs during meiosis and initiates 'homing', a genetic event that converts a VMA1 allele lacking the endonuclease coding sequence into one that contains it [1].
• The TFP1 gene of the yeast Saccharomyces cerevisiae encodes two proteins: the 69-kilodalton (kD) catalytic subunit of the vacuolar proton-translocating adenosine triphosphatase (H(+)-ATPase) and a 50-kD protein [2].
• Protein splicing of the yeast TFP1 intervening protein sequence: a model for self-excision [3].
• The Tfp1 spacer protein belongs to a new class of intervening sequences that are excised at the protein rather than the RNA level [3].

Biological context of TFP1

• Protein splicing converts the yeast TFP1 gene product to the 69-kD subunit of the vacuolar H(+)-adenosine triphosphatase [2].
• Based on the peptide sequence information, a 39-base oligonucleotide probe was synthesized, and the gene encoding the subunit (VMA1) was isolated from a genomic DNA library by hybridization [4].
• Molecular structure of a gene, VMA1, encoding the catalytic subunit of H(+)-translocating adenosine triphosphatase from vacuolar membranes of Saccharomyces cerevisiae [4].
• In contrast to S. cerevisiae, however, where disruption of the VMA1 gene was conditionally lethal, and to N. crassa, where viable disruptants could not be isolated, disruption of the VMA1 gene in A. gossypii did not cause a lethal phenotype [5].
• To investigate the function of residues at the catalytic nucleotide binding site of the V-ATPase, we have carried out site-directed mutagenesis of the VMA1 gene encoding the A subunit of the V-ATPase in yeast [6].

Anatomical context of TFP1

• Functional complementation of yeast vma1 delta cells by a plant subunit A homolog rescues the mutant phenotype and partially restores vacuolar H(+)-ATPase activity [7].
• Cloning and sequencing of cDNA encoding the putative insect plasma membrane V-ATPase subunit A [8].

Associations of TFP1 with chemical compounds

• The VMA1 gene has proven to be the same gene as the TFP1 gene (Shih, C.-K., Wagner, R., Feinstein, S., Kanik-Ennulat, C., and Neff, N. (1988) Mol. Cell. Biol. 8, 3094-3103) whose dominant mutant allele (TFP1-408) confers a dominant trifluoperazine resistance and Ca2(+)-sensitive growth [4].
• A protein splicing model is presented in which asparagine rearrangement initiates the self-excision of the spacer protein from the Tfp1 precursor [3].
• In this work, we randomized the conserved valine triplet residues three amino acids upstream of the C-terminal splicing junction in the Vma1 protozyme and found that these site-specific random mutations interfere with normal protein splicing to different extents [9].
• Eight different mutant alleles of VMA1 were examined for levels of the catalytic subunit and other subunits of the enzyme, assembly of the ATPase complex, targeting to the vacuolar membrane, and concanamycin A-sensitive ATPase activity [10].
• Single deletion of VMA1 and genes encoding other V-ATPase subunits led to a more extended period of adaptation and to slower growth under 2,4-D stress [11].

Regulatory relationships of TFP1

• We show also that GSH11 is not expressed in a VDE-deleted strain and that inability to express the GSH11 of this strain is overcome by introduction of the coding region of VDE or the entire VMA1 gene [12].

Other interactions of TFP1

• The synthesis, assembly, and targeting of three of the peripheral subunits (the 69-, 60-, and 42-kDa subunits) and two of the integral membrane subunits (the 100- and 17-kDa subunits) were examined in mutant yeast cells containing chromosomal deletions in the TFP1, VAT2, or VMA3 genes, which encode the 69-, 60-, and 17-kDa subunits, respectively [13].
• No alleles of the VAT2 or TFP1 genes (known to encode subunits of the vacuolar H(+)-ATPase) were identified in the Vph- screen [14].

Analytical, diagnostic and therapeutic context of TFP1

• Although the reason for the discrepancy in molecular mass is unclear at present, these results suggest that a novel processing mechanism, which might involve a post-translational excision of the internal region followed by peptide ligation, operates on the yeast VMA1 product [4].
• To investigate the functional role of this region, site-directed mutagenesis has been performed on the VMA1 gene that encodes subunit A in yeast [15].
• Cloning was achieved by polymerase chain reaction using oligonucleotide primers derived form conserved sequences of the Vma1 proteins from yeast and filamentous fungi [5].

References