The Saccharomyces cerevisiae FLO1 flocculation gene encodes for a cell surface protein

Abstract

The sequencing of a 6619 bp region encoding for a flocculation gene previously cloned from a strain defined as FLO5 (Bidard et al., 1994) has revealed that it was a FLO1 gene. The FLO1 gene product has been localized at the cell surface of the yeast cell by immunofluorescent microscopy. The Flo1 protein contains four regions with repeated sequences which account for about 70% of the amino acids of this protein. A functional analysis of the major repeated region has revealed that it plays an important role in determining the flocculation level. A gene disruption experiment has shown that FLO5 strain STX 347-1D contains at least two flocculation genes of the FLO1 type but that they are supposed to be inactive and do not contribute to its flocculation. However, enzyme-linked immunosorbent assays performed on intact cells have revealed that a protein expressed at the cell surface of the FLO5 strain STX 347-1D is antigenically related to Flo1p. A deletion analysis of the 5' region of the FLO1 gene has shown that the expression is submitted to controls which depend on the genetic background of the strain.

The Saccharomyces cerevisiae MADS-Box Transcription Factor Rlm1 Is a Target for the Mpk1 Mitogen-Activated Protein Kinase Pathway

“…MADS-box residue 1 is a glycine in all three proteins, while in the 11 to 15 region, residue 13, which is crucial for but not sufficient to determine MEF2 binding specificity, is an acidic residue, found previously only in MEF2 family members (36,47). This conservation suggests that the yeast proteins may recognize a consensus sequence similar to that of MEF2, CTA(T/A) 4 TAG. The C-terminal regions of Smp1 and Rlm1 are also related, but more distantly, exhibiting 27% identity and an additional 15% similarity.…”

“…We have characterized the DNA binding properties of two yeast MADS-box proteins, Rlm1 (54) and Smp1 (encoded by the YBR182C open reading frame [10,14]), whose DNA-binding and dimerization domains are most closely related to those of the metazoan MEF2 family of transcription factors (39,58). The two proteins indeed exhibit distinct but related MEF2-like DNAbinding specificities: although both proteins can bind the MEF2 core consensus sequence CTA(T/A) 4 TAG, Smp1 exhibits an additional sequence preference, RYT(not C), at the 5Ј side of the MEF2 core consensus. Smp1 can therefore bind only a subset of MEF2 motifs efficiently.…”

“…We searched the S. cerevisiae sequence database for occurrences of the MEF2 core consensus CTA(A/T) 4 TAG within the 500 bp 5Ј to the translational initiation codon. We excluded sites that mismatch this consensus even though they can function as functional Rlm1-binding sites in vivo, since they are difficult to distinguish from TATA boxes and A/T-rich elements.…”

Breeding of flocculent industrial alcohol yeast strains by self-cloning of the flocculation gene FLO1 and repeated-batch fermentation by transformants.

“…FLO1, which is one of the dominant flocculation genes, has been cloned and sequenced by three groups (Bidard et al, 1995;Teunissen et al, 1993;Watari et al, 1994b). Recently it was shown that FLO1 should be a structural gene coding for a cell surface protein, which has a key role in the mechanism of yeast flocculation, because of the localization of its product (Bidard et al, 1995), the similarity of the N-terminal sequence between the putative FLO1 product and a protein that was purified from flocculent yeast cell surface, and the stimulative effect on the flocculation ability of the yeast cells (Straver, 1994 Bunkyo-ku, Tokyo 113-8657, Japan (Received July 17, 1998; Accepted October 8, 1998) A nonflocculent industrial polyploid yeast strain, Saccharomyces cerevisiae 396-9-6V, was converted to a flocculent one by introducing a functional FLO1 gene at the URA3 locus.…”

“…Recently it was shown that FLO1 should be a structural gene coding for a cell surface protein, which has a key role in the mechanism of yeast flocculation, because of the localization of its product (Bidard et al, 1995), the similarity of the N-terminal sequence between the putative FLO1 product and a protein that was purified from flocculent yeast cell surface, and the stimulative effect on the flocculation ability of the yeast cells (Straver, 1994). Moreover, introducing FLO1 into nonflocculent beer yeast strains as plasmids and by the chromosomal inBreeding of flocculent industrial alcohol yeast strains by self-cloning of the flocculation gene FLO1 and repeated-batch fermentation by transformants tegration method conferred a flocculent phenotype (Watari et al, 1991(Watari et al, , 1994a.…”