Scarcity of <i>ars</i> sequences isolated in a morphogenesis mutant of the yeast <i>Yarrowia lipolytica</i>

Fournier, P.; Guyaneux, L.; Chasles, Marion; Gaillardin, Claude

doi:10.1002/yea.320070104

Cited by 51 publications

(30 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Cells from smooth colonies were observed only in the budding form of growth. The frequency of mutants was 8.7 ϫ 10 Ϫ4 , similar to those described for Y. lipolytica by other authors (18,48).…”

Section: Isolation and Characterization Of Morphological Mutantssupporting

confidence: 87%

“…lipolytica is a dimorphic heterothallic yeast (3) that is unusual in both the structure of its genes coding for rRNA (17) and in its relationship to other yeasts (2). Y. lipolytica is amenable to genetic analysis (48), and DNA-mediated integration (12,20) and autonomous transformation systems (18) have been developed. Mutations in the SEC14 gene (42) and deletion of XPR6 (16) have strong effects on the yeast-to-hypha transition.…”

mentioning

confidence: 99%

See 1 more Smart Citation

HOY1, a Homeo Gene Required for Hyphal Formation inYarrowia lipolytica

Torres-Guzmán

Domínguez

1997

Molecular and Cellular Biology

View full text Add to dashboard Cite

The dimorphic fungus Yarrowia lipolytica grows to form hyphae either in rich media or in media with GlcNAc as a carbon source. A visual screening, called FIL (filamentation minus), for Y. lipolytica yeast growth mutants has been developed. The FIL screen was used to identify three Y. lipolytica genes that abolish hypha formation in all media assayed. Y. lipolytica HOY1, a gene whose deletion prevents the yeast-hypha transition both in liquid and solid media, was characterized. HOY1 is predicted to encode a 509-amino-acid protein with a homeodomain homologous to that found in the chicken Hox4.8 gene. Analysis of the protein predicts a nuclear location. These observations suggest that Hoy1p may function as a transcriptional regulatory protein. In disrupted strains, reintroduction of HOY1 restored the capacity for hypha formation. Northern blot hybridization revealed the HOY1 transcript to be approximately 1.6 kb. Expression of this gene was detected when Y. lipolytica grew as a budding yeast, but an increase in its expression was observed by 1 h after cells had been induced to form hyphae. The possible functions of HOY1 in hyphal growth and the uses of the FIL screen to identify morphogenetic regulatory genes from heterologous organisms are discussed.The yeast-to-hypha morphological transition (dimorphism) is typical of many pathogenic fungi (62). The dimorphic transition is a freely reversible process that can be induced by changes in many parameters (56). Much attention has been focused on Candida albicans as a model for analyzing dimorphism because it is the most frequently isolated fungal pathogen in humans. However, although several groups have reported the isolation of mutants which persist in either the yeast (10) or hyphal (21, 30) form, analysis of these mutants is hampered by the difficulties inherent to genetic manipulations of this asexual diploid organism.Two approaches have been successfully used to carry out the analysis of dimorphism. With one of them, differential hybridization screening (7), several genes that are differentially expressed during morphogenesis have been isolated in C. albicans (i.e., ECE1, expressed in association with cell elongation, and PHR1, which is differentially regulated in response to the pH of the growth medium). Deletion of PHR1 results in a pH-conditional defect in morphogenesis (59).The second approach consists of cloning Candida homologs of Saccharomyces cerevisiae genes known to regulate pseudofilamentous growth. Under conditions of nutrient limitation (i.e., nitrogen starvation), S. cerevisiae undergoes a dimorphic transition to growth of pseudohyphae, linear chains of elongated cells in which the daughters remain attached to the mothers (23, 24). In this context, several C. albicans genes that are members of a Candida map kinase (MAPK) cascade, i.e., CPH1 (40) or ACPR (43), HST7 (11), and CST20 (36, 39), have been isolated by complementation of the corresponding Saccharomyces mutants, i.e., STE12, STE7, and STE20, respectively (11,36,39,40,43). When C. albicans st...

show abstract

Section: Isolation and Characterization Of Morphological Mutantssupporting

confidence: 87%

mentioning

confidence: 99%

HOY1, a Homeo Gene Required for Hyphal Formation inYarrowia lipolytica

Torres-Guzmán

Domínguez

1997

Molecular and Cellular Biology

View full text Add to dashboard Cite

show abstract

“…From a Y. lipolytica gene library, we had previously isolated the ARS18 and ARS68 sequences that are able to promote extrachromosomal replication in this yeast (27). We had shown that both ARS elements also have the ability to confer centromere-like segregation properties on yeast plasmids, and we had localized these characteristics to a 410-bp region in the case of ARS18 (26).…”

Section: Discussionmentioning

confidence: 99%

“…We previously cloned on plasmids two sequences (ARS18 and ARS68) able to promote extrachromosomal replication (27). These two ARS plasmids displayed a behavior different from that of traditional ARS elements in S. cerevisiae: low copy number, higher mitotic stability, and scarcity in a genomic DNA library.…”

Section: Although the Nature Of Higher Eukaryotic Replication Originsmentioning

confidence: 99%

“…The mitotic stability of plasmids was measured qualitatively by cultivating the yeast transformants in complete medium for about 15 to 20 generations, followed by streaking on complete medium and replica plating on selective and nonselective minimal media. To measure the percentage of plasmid loss per generation quantitatively, we followed the procedure already described (27).…”

Section: Although the Nature Of Higher Eukaryotic Replication Originsmentioning

confidence: 99%

See 1 more Smart Citation

An Origin of Replication and a Centromere Are Both Needed To Establish a Replicative Plasmid in the YeastYarrowia lipolytica

Vernis

Abbas

Chasles

et al. 1997

Molecular and Cellular Biology

View full text Add to dashboard Cite

. We have used the integration properties of centromeric sequences to show that all Y. lipolytica ARS elements so far isolated are composed of both a replication origin and a centromere. The sequence and the distance between the origin and centromere do not seem to play a critical role, and many origins can function in association with one given centromere. A centromeric plasmid can therefore be used to clone putative chromosomal origins coming from several genomic locations, which confer the replicative property on the plasmid. The DNA sequences responsible for initiation in plasmids are short (several hundred base pairs) stretches which map close to or at replication initiation sites in the chromosome. Their chromosomal deletion abolishes initiation, but changing their chromosomal environment does not. Although the nature of higher eukaryotic replication originsis not yet clear (12), that of origins in the yeast Saccharomyces cerevisiae is relatively well understood. It has been possible to clone S. cerevisiae genomic sequences that confer on a plasmid the ability to replicate extrachromosomally in this yeast. These sequences are called ARS (autonomously replicating sequence) elements. Most ARS elements are active as origins in their chromosomal context, as shown by two-dimensional (2D) gel replicon mapping studies (8,44,62). ARS elements are usually smaller than 150 bp, and they contain an essential motif that matches the 11-bp ARS consensus sequence (ACS; WTT TAYRTTTW) in at least 9 of 11 positions (61, 72). The ACS is essential for initiation of replication, both on plasmids and in the chromosome (17). Also essential is domain B, located at the 3Ј end of the ACS (54,55,76). Depending on the ARS element, domain B can be subdivided into two or three subdomains with variable sequences but conserved roles (42, 66). Finally, a DNA unwinding element is frequently present in ARS elements and is important for replication of plasmids (60) and chromosomes (41). Initiation at ARS elements is under strict cell cycle control (reviewed in reference 18).In contrast to the defined origin sequences of S. cerevisiae, the degree to which specific sequences are employed as origins in the differentiated cells of higher organisms is not yet clear. Most studies employing labeling techniques suggest that initiation takes place at specific sites or in very small (a few kilobases or less) initiation zones (15,19,35). In contrast, all studies employing 2D gel replicon mapping techniques-and some studies using labeling techniques (31, 71)-suggest that initiation can take place at any of numerous locations within large initiation zones of 50 kb or more (reviewed in reference 36). Furthermore, in contrast to the discrete ARS elements of S. cerevisiae, most human DNA pieces larger than ϳ10 kb permit extrachromosomal plasmid replication (38,51). In this case, initiation does not start at a preferred locus, a result which is also observed in plasmid transformation in Xenopus eggs (46,53). Demonstrations that the choice of initiation sites ...

show abstract