scholarly journals Functional Differentiation of tbf1 Orthologues in Fission and Budding Yeasts

2008 ◽  
Vol 8 (2) ◽  
pp. 207-216 ◽  
Author(s):  
Moira M. Cockell ◽  
Libera Lo Presti ◽  
Lorenzo Cerutti ◽  
Elena Cano Del Rosario ◽  
Philippe M. Hauser ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Family ◽  
Essential Gene ◽  
Pneumocystis Carinii ◽  
Ectopic Expression ◽  
Functional Differentiation ◽  
Regulation Of Transcription ◽  
Global Regulation ◽  
Telomere Function ◽  
Essential Function

ABSTRACT In Saccharomyces cerevisiae, TBF1, an essential gene, influences telomere function but also has other roles in the global regulation of transcription. We have identified a new member of the tbf1 gene family in the mammalian pathogen Pneumocystis carinii. We demonstrate by transspecies complementation that its ectopic expression can provide the essential functions of Schizosaccharomyces pombe tbf1 but that there is no rescue between fission and budding yeast orthologues. Our findings indicate that an essential function of this family of proteins has diverged in the budding and fission yeasts and suggest that effects on telomere length or structure are not the primary cause of inviability in S. pombe tbf1 null strains.

scholarly journals Functional Characterization of Pneumocystis carinii brl1 by Transspecies Complementation Analysis

2007 ◽  
Vol 6 (12) ◽  
pp. 2448-2452 ◽  
Author(s):  
Libera Lo Presti ◽  
Moira Cockell ◽  
Lorenzo Cerutti ◽  
Viesturs Simanis ◽  
Philippe M. Hauser
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Membrane Proteins ◽  
Nuclear Membrane ◽  
Opportunistic Infections ◽  
Functional Characterization ◽  
Pneumocystis Carinii ◽  
Ectopic Expression ◽  
Functional Complementation ◽  
Null Alleles

ABSTRACT Pneumocystis jirovecii is a fungus which causes severe opportunistic infections in immunocompromised humans. The brl1 gene of P. carinii infecting rats was identified and characterized by using bioinformatics in conjunction with functional complementation in Saccharomyces cerevisiae and Schizosaccharomyces pombe. The ectopic expression of this gene rescues null alleles of essential nuclear membrane proteins of the Brr6/Brl1 family in both yeasts.

scholarly journals The essential function of Swc4p - a protein shared by two chromatin-modifying complexes of the yeast Saccharomyces cerevisiae - resides within its N-terminal part.

2008 ◽  
Vol 55 (3) ◽  
pp. 603-612 ◽  
Author(s):  
Arkadiusz Miciałkiewicz ◽  
Anna Chełstowska
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Essential Gene ◽  
Random Mutagenesis ◽  
Growth Conditions ◽  
Histone H2a ◽  
Terminal Part ◽  
Yeast Saccharomyces Cerevisiae ◽  
Chromatin Remodeling Complexes ◽  
Essential Function

The Swc4p protein, encoded by an essential gene, is shared by two chromatin-remodeling complexes in Saccharomyces cerevisiae cells: NuA4 (nucleosome acetyltransferase of H4) and SWR1. The SWR1 complex catalyzes ATP-dependent exchange of the nucleosomal histone H2A for H2AZ (Htz1p). The activity of NuA4 is responsible mainly for the acetylation of the H4 histone but also for the acetylation of H2A and H2AZ. In this work we investigated the role of the Swc4p protein. Using random mutagenesis we isolated a collection of swc4 mutants and showed that the essential function of Swc4p resides in its N-terminal part, within the first 269 amino acids of the 476-amino acid-long protein. We also demonstrated that Swc4p is able to accommodate numerous mutations without losing its functionality under standard growth conditions. However, when swc4 mutants were exposed to methyl methanesulfonate (MMS), hydroxyurea or benomyl, severe growth deficiencies appeared, pointing to an involvement of Swc4p in many chromatin-based processes. The mutants' phenotypes did not result from an impairment of histone acetylation, as in the mutant which bears the shortest isolated variant of truncated Swc4p, the level of overall H4 acetylation was unchanged.

scholarly journals Regulatory Mechanisms Controlling Expression of the DAN/TIR Mannoprotein Genes During Anaerobic Remodeling of the Cell Wall in Saccharomyces cerevisiae

Genetics ◽  
2001 ◽  
Vol 157 (3) ◽  
pp. 1169-1177
Author(s):  
Natalia E Abramova ◽  
Brian D Cohen ◽  
Odeniel Sertil ◽  
Rachna Kapoor ◽  
Kelvin J A Davies ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Consensus Sequence ◽  
Ectopic Expression ◽  
Constitutive Expression ◽  
Anaerobic Growth ◽  
Zinc Cluster ◽  
Sterol Transport ◽  
Genes Encoding ◽  
Altered Regulation ◽  
Repression Domain

Abstract The DAN/TIR genes of Saccharomyces cerevisiae encode homologous mannoproteins, some of which are essential for anaerobic growth. Expression of these genes is induced during anaerobiosis and in some cases during cold shock. We show that several heme-responsive mechanisms combine to regulate DAN/TIR gene expression. The first mechanism employs two repression factors, Mox1 and Mox2, and an activation factor, Mox4 (for mannoprotein regulation by oxygen). The genes encoding these proteins were identified by selecting for recessive mutants with altered regulation of a dan1::ura3 fusion. MOX4 is identical to UPC2, encoding a binucleate zinc cluster protein controlling expression of an anaerobic sterol transport system. Mox4/Upc2 is required for expression of all the DAN/TIR genes. It appears to act through a consensus sequence termed the AR1 site, as does Mox2. The noninducible mox4Δ allele was epistatic to the constitutive mox1 and mox2 mutations, suggesting that Mox1 and Mox2 modulate activation by Mox4 in a heme-dependent fashion. Mutations in a putative repression domain in Mox4 caused constitutive expression of the DAN/TIR genes, indicating a role for this domain in heme repression. MOX4 expression is induced both in anaerobic and cold-shocked cells, so heme may also regulate DAN/TIR expression through inhibition of expression of MOX4. Indeed, ectopic expression of MOX4 in aerobic cells resulted in partially constitutive expression of DAN1. Heme also regulates expression of some of the DAN/TIR genes through the Rox7 repressor, which also controls expression of the hypoxic gene ANB1. In addition Rox1, another heme-responsive repressor, and the global repressors Tup1 and Ssn6 are also required for full aerobic repression of these genes.

scholarly journals The PBN1 Gene of Saccharomyces cerevisiae: An Essential Gene That Is Required for the Post-translational Processing of the Protease B Precursor

Genetics ◽  
1998 ◽  
Vol 149 (3) ◽  
pp. 1277-1292 ◽  
Author(s):  
Rajesh R Naik ◽  
Elizabeth W Jones
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Secretory Pathway ◽  
Transmembrane Domain ◽  
Essential Gene ◽  
Signal Sequence ◽  
Signal Peptidase ◽  
Amino Terminal ◽  
Autocatalytic Cleavage ◽  
Protease B ◽  
Chromosome Iii

Abstract The vacuolar hydrolase protease B in Saccharomyces cerevisiae is synthesized as an inactive precursor (Prb1p). The precursor undergoes post-translational modifications while transiting the secretory pathway. In addition to N- and O -linked glycosylations, four proteolytic cleavages occur during the maturation of Prb1p. Removal of the signal peptide by signal peptidase and the autocatalytic cleavage of the large aminoterminal propeptide occur in the endoplasmic reticulum (ER). Two carboxy-terminal cleavages of the post regions occur in the vacuole: the first cleavage is catalyzed by protease A and the second results from autocatalysis. We have isolated a mutant, pbn1-1, that exhibits a defect in the ER processing of Prb1p. The autocatalytic cleavage of the propeptide from Prb1p does not occur and Prb1p is rapidly degraded in the cytosol. PBN1 was cloned and is identical to YCL052c on chromosome III. PBN1 is an essential gene that encodes a novel protein. Pbn1p is predicted to contain a sub-C-terminal transmembrane domain but no signal sequence. A functional HA epitope-tagged Pbn1p fusion localizes to the ER. Pbn1p is N-glycosylated in its amino-terminal domain, indicating a lumenal orientation despite the lack of a signal sequence. Based on these results, we propose that one of the functions of Pbn1p is to aid in the autocatalytic processing of Prb1p.

scholarly journals Essential and nonessential histone H2A variants in Tetrahymena thermophila.

1996 ◽  
Vol 16 (8) ◽  
pp. 4305-4311 ◽  
Author(s):  
X Liu ◽  
B Li ◽  
GorovskyMA
Keyword(s):  
Tetrahymena Thermophila ◽  
Essential Gene ◽  
Histone Variants ◽  
Gene Replacement ◽  
Histone H2a ◽  
Gene Encoding ◽  
Genes Encoding ◽  
Simple Mass ◽  
Essential Function ◽  
High Degree

Although variants have been identified for every class of histone, their functions remain unknown. We have been studying the histone H2A variant hv1 in the ciliated protozoan Tetrahymena thermophila. Sequence analysis indicates that hv1 belongs to the H2A.F/Z type of histone variants. On the basis of the high degree of evolutionary conservation of this class of histones, they are proposed to have one or more distinct and essential functions that cannot be performed by their major H2A counterparts. Considerable evidence supports the hypothesis that the hv1 protein in T. thermophila and hv1-like proteins in other eukaryotes are associated with active chromatin. In T. thermophila, simple mass transformation and gene replacement techniques have recently become available. In this report, we demonstrate that either the HTA1 gene or the HTA2 gene, encoding the major H2As, can be completely replaced by disrupted genes in the polyploid, transcriptionally active macronucleus, indicating that neither of the two genes is essential. However, only some of the HTA3 genes encoding hv1 can be replaced by disrupted genes, indicating that the H2A.F/Z type variants have an essential function that cannot be performed by the major H2A genes. Thus, an essential gene in T. thermophila can be defined by the fact that it can be partially, but not completely, eliminated from the polyploid macronucleus. To our knowledge, this study represents the first use of gene disruption technology to study core histone gene function in any organism other than yeast and the first demonstration of an essential gene in T. thermophila using these methods. When a rescuing plasmid carrying a wild-type HTA3 gene was introduced into the T. thermophila cells, the endogenous chromosomal HTA3 could be completely replaced, defining a gene replacement strategy that can be used to analyze the function of essential genes.

Pneumocystis carinii BCK1 Complements the Saccharomyces cerevisiae Cell Wall Integrity Pathway

2003 ◽  
Vol 50 (s1) ◽  
pp. 676-677 ◽  
Author(s):  
PAWAN K. VOHRA ◽  
THEODORE J. KOTTOM ◽  
ANDREW H. LIMPER ◽  
CHARLES F. THOMAS
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Wall ◽  
Pneumocystis Carinii ◽  
Cell Wall Integrity ◽  
Cell Wall Integrity Pathway

scholarly journals GSP1 and GSP2, genetic suppressors of the prp20-1 mutant in Saccharomyces cerevisiae: GTP-binding proteins involved in the maintenance of nuclear organization.

1993 ◽  
Vol 13 (4) ◽  
pp. 2152-2161 ◽  
Author(s):  
P Belhumeur ◽  
A Lee ◽  
R Tam ◽  
T DiPaolo ◽  
N Fortin ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Replication ◽  
Essential Gene ◽  
Negative Control ◽  
Temperature Sensitive ◽  
Vitro Assay ◽  
Gtp Binding ◽  
Genetic Suppressors ◽  
Multicopy Suppressors

The temperature-sensitive mutation prp20-1 of Saccharomyces cerevisiae exhibits a pleiotropic phenotype associated with a general failure to maintain a proper organization of the nucleus. Its mammalian homolog, RCC1, is not only reported to be involved in the negative control of chromosome condensation but is also believed to assist in the coupling of DNA replication to the entry into mitosis. Recent studies on Xenopus RCC1 have strongly suggested a further role for this protein in the formation or maintenance of the DNA replication machinery. To elucidate the nature of the various components required for this PRP20 control pathway in S. cerevisiae, we undertook a search for multicopy suppressors of a prp20 thermosensitive mutant. Two genes, GSP1 and GSP2, were identified that encode almost identical polypeptides of 219 and 220 amino acids. Sequence analyses of these proteins show them to contain the ras consensus domains involved in GTP binding and metabolism. The levels of the GSP1 transcript are about 10-fold those of GSP2. As for S. cerevisiae RAS2, GSP2 expression exhibits carbon source dependency, while GSP1 expression does not. GSP1 is an essential gene, and GSP2 is not required for cell viability. We show that GSP1p is nuclear, that it can bind GTP in an in vitro assay, and finally, that a mutation in GSP1p which activates small ras-like proteins by increasing the stability of the GTP-bound form causes a dominant lethal phenotype. We believe that these two gene products may serve in regulating the activities of the multicomponent PRP20 complex.

A new essential gene of Saccharomyces cerevisiae, a defect in it may result in instability of nucleus

1992 ◽  
Vol 200 (1) ◽  
pp. 48-57 ◽  
Author(s):  
Hideaki Nisogi ◽  
Kin-Ichiro Kominami ◽  
Kazuma Tanaka ◽  
Akio Toh-E
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Essential Gene

The Drosophila homeobox gene optix is capable of inducing ectopic eyes by an eyeless-independent mechanism

Development ◽  
2000 ◽  
Vol 127 (9) ◽  
pp. 1879-1886 ◽  
Author(s):  
M. Seimiya ◽  
W.J. Gehring
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Gene Family ◽  
Eye Development ◽  
Ectopic Expression ◽  
Amino Acid Sequence Similarity ◽  
Sine Oculis ◽  
High Amino Acid ◽  
Independent Mechanism ◽  
Ectopic Eyes

optix is a new member of the Six/so gene family from Drosophila that contains both a six domain and a homeodomain. Because of its high amino acid sequence similarity with the mouse Six3 gene, optix is considered to be the orthologous gene from Drosophila rather than sine oculis, as previously believed. optix expression was detected in the eye, wing and haltere imaginal discs. Ectopic expression of optix leads to the formation of ectopic eyes suggesting that optix has important functions in eye development. Although optix and sine oculis belong to the same gene family (Six/so) and share a high degree of amino acid sequence identity, there are a number of factors which suggest that their developmental roles are different: (1) the expression patterns of optix and sine oculis are clearly distinct; (2) sine oculis acts downstream of eyeless, whereas optix is expressed independently of eyeless; (3) sine oculis functions synergistically with eyes absent in eye development whereas optix does not; (4) ectopic expression of optix alone, but not of sine oculis can induce ectopic eyes in the antennal disc. These results suggest that optix is involved in eye morphogenesis by an eyeless-independent mechanism.

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