Isolation and sequence analysis of the gene encoding translation elongation factor 3 from Candida albicans.

The structural gene encoding translation elongation factor 3 (EF-3) has been cloned from a Candida albicans genomic library by hybridization to a Saccharomyces cerevisiae probe containing the Saccharomyces gene, YEF3 (Sandbaken et al., 1990b). The sequences were shown to be functionally homologous to the Saccharomyces gene by three criteria: (1) a Saccharomyces strain transformed with a high copy plasmid containing CaEF3 sequences overproduces the EF-3 peptide two-fold; (2) extracts from this strain exhibit a two-fold increase in the EF-3-catalysed, ribosome-dependent ATPase activity (Kamath and Chakraburtty, 1988); and (3) the Candida gene complements a Saccharomyces null mutant. The coding region, identified by DNA sequencing, indicates that CaEF3 encodes a 1050 amino acid polypeptide having a potential molecular weight of 116,865 Da. This protein shows 77% overall identity to the Saccharomyces YEF3 gene, with a significantly greater identity (94%) concentrated in the region of the protein thought to contain the catalytic domain of EF-3 (Sandbaken et al., 1990a). The upstream non-coding region contains T-rich regions typical of many yeast genes and several potential RAP1/GRF1 elements shown to regulate expression of a number of translational genes (Mager, 1988). The data confirm a high degree of conservation for EF-3 among the two organisms.     

Isolation and sequencing of the Candida albicans MSI3, a putative novel member of the HSP70 family

We have reported previously that the expression of CGR1 increased at an early stage of the yeast-mycelial transition (morphogenesis) in Candida albicans. We now show that Cgr1p interacts in a yeast two-hybrid system with the C. albicans Msi3p (CaMsi3p), a putative novel member of the heat shock protein 70 (HSP70) family. The DNA sequence of CaMSI3 encodes a predicted protein of 702 amino acids with a molecular mass of 78.6 kDa. The amino acid sequence of CaMsi3p is 63% identical to Msi3p/Sse1p of the HSP70 family of Saccharomyces cerevisiae. Further, CaMSI3 complemented the temperature-sensitive phenotype of the msi3(-) mutant of S. cerevisiae. Other heat shock proteins of C. albicans are required for morphogenesis and are highly antigenic. These observations suggest that CaMSI3 may well provide functions for this organism unrelated to a heat shock function. The DDBJ Accession No. for the sequence reported in this paper is AB061274.     

Cloning and characterization of a novel NAD+‐dependent glyceraldehyde‐3‐phosphate dehydrogenase gene from Candida glycerinogenes and use of its promoter

A 3950 bp genomic fragment from Candida glycerinogenes, WL2002‐5, containing the CgGAP gene encoding a glyceraldehyde‐3‐phosphate dehydrogenase homologous to GAP genes in other yeasts using degenerate primers, was cloned and characterized with inverse PCR. Sequence analysis revealed a 1164 bp open reading frame encoding a putative peptide of 387 deduced amino acids, with a molecular mass of 36 kDa. The CgGAP protein consisted of an N‐terminal NAD⁺‐binding domain and a central catalytic domain. Six stress‐response elements were found in the upstream region of the CgGAP gene. The influence of CgGAP on glycolysis was investigated. Functional analysis revealed that Saccharomyces cerevisiae transformed with CgGAP was restored to the wild‐type phenotype when cultured in high‐osmolarity medium, suggesting that it is a functional GAP protein. Promoter studies in S. cerevisiae using the green fluorescent protein (gfp) gene as a reporter showed that the GAP promoter (P_CgGAP) is constitutively expressed in S. cerevisiae cells grown on glucose. Copyright © 2013 John Wiley & Sons, Ltd.     

In vivo selectively infective phage as a tool to detect protein interactions: evaluation of a novel vector system with yeast Ste7p-Fus3p interacting proteins

The selectively infective phage (SIP) approach allows rapid identification of interacting proteins by linking protein-protein interaction to phage infectivity. Infection of E. coli by filamentous phage depends on viral g3p. This protein consists of three domains, N1, N2 and CT. Phages lacking the N1 domain are non-infective unless a bait (X)-prey (Y) interaction links it to phage anchored N2-CT domains. We have developed all the vectors required for an in vivo selectively infective phage strategy (SIP). This includes a bait vector, pG3N1, a prey vector, pHOS41, and a gene III deletion helper phage, HPd3. The bait vector pG3N1 allows expression of a bait protein (X) fused to the C-terminus of the N1 domain. The prey vector pHOS41 allows expression of prey (Y) proteins, fused to the N-terminus of the N2-CT domains. The gene III deletion helper phage delivers all phage proteins necessary for phage production, except g3p. Escherichia coli transformed with these three vectors produces non-infective phages unless a bait-prey interaction links the g3p domains. Fus3p and Ste7p, two proteins from the Saccharomyces cerevisiae pheromone-responsive pathway have been cloned to evaluate the SIP strategy. The presence of the interacting N1-Fus3p adapter increased the infectivity of Ste7p-N2-CT phages approximately 1400-fold, which makes SIP a promising technology for the detection and further investigation of interacting proteins.