HO gene polymorphism in Saccharomyces industrial yeasts and application of novel HO genes to convert homothallism to heterothallism in combination with the mating-type detection cassette

2001 ◽  
Vol 55 (3) ◽  
pp. 333-340 ◽  
Author(s):  
Yukio Tamai ◽  
Keiko Tanaka ◽  
Yoshinobu Kaneko ◽  
Satoshi Harashima
Keyword(s):  
Gene Polymorphism ◽  
Mating Type ◽  
Ho Gene ◽  
Industrial Yeasts

INTERCONVERSION OF YEAST MATING TYPES II. RESTORATION OF MATING ABILITY TO STERILE MUTANTS IN HOMOTHALLIC AND HETEROTHALLIC STRAINS

Genetics ◽  
1977 ◽  
Vol 85 (3) ◽  
pp. 373A-393
Author(s):  
James B Hicks ◽  
Ira Herskowitz
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mating Type ◽  
Yeast Cells ◽  
Mating Types ◽  
Yeast Saccharomyces Cerevisiae ◽  
Type Locus ◽  
Mating Ability ◽  
Mating Type Locus ◽  
Regulatory Information ◽  
Ho Gene

ABSTRACT The two mating types of the yeast Saccharomyces cerevisiae can be interconverted in both homothallic and heterothallic strains. Previous work indicates that all yeast cells contain the information to be both a and α and that the HO gene (in homothallic strains) promotes a change in mating type by causing a change at the mating type locus itself. In both heterothallic and homothallic strains, a defective α mating type locus can be converted to a functional a locus and subsequently to a functional α locus. In contrast, action of the HO gene does not restore mating ability to a strain defective in another gene for mating which is not at the mating type locus. These observations indicate that a yeast cell contains an additional copy (or copies) of α information, and lead to the "cassette" model for mating type interconversion. In this model, HM  a and hmα loci are blocs of unexpressed α regulatory information, and HMα and hm  a loci are blocs of unexpressed a regulatory information. These blocs are silent because they lack an essential site for expression, and become active upon insertion of this information (or a copy of the information) into the mating type locus by action of the HO gene.

scholarly journals MUTATION OF A HETEROTHALLIC STRAIN TO HOMOTHALLISM

Genetics ◽  
1975 ◽  
Vol 80 (1) ◽  
pp. 77-85
Author(s):  
Anita K Hopper ◽  
Benjamin D Hall
Keyword(s):  
Mating Type ◽  
Diploid Strain ◽  
New Gene ◽  
Ho Gene

ABSTRACT Upon mutagenesis, a heterothallic αα diploid strain mutated to homothallism. The gene confering homothallism is nuclear, recessive, and unlinked to mating type. This gene is not allelic to the HO gene, which is responsible for previously described instances of homothallism in yeast. We have designated this new gene for homothallism as cmt (change of mating type).

scholarly journals Structure of the Saccharomyces cerevisiae HO gene and analysis of its upstream regulatory region

1986 ◽  
Vol 6 (12) ◽  
pp. 4281-4294
Author(s):  
D W Russell ◽  
R Jensen ◽  
M J Zoller ◽  
J Burke ◽  
B Errede ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mating Type ◽  
Dna Sequences ◽  
Regulatory Region ◽  
Initiation Codon ◽  
Upstream Region ◽  
Lacz Gene ◽  
Type Locus ◽  
Reading Frame ◽  
Ho Gene

The HO gene product of Saccharomyces cerevisiae is a site-specific endonuclease that initiates mating type interconversion. We have determined the nucleotide sequence of a 3,129-base-pair (bp) segment containing HO. The segment contains a single long open reading frame encoding a polypeptide of 586 amino acids, which has unusual (unbiased) codon usage and is preceded by 762 bp of upstream region. The predicted HO protein is basic (16% lysine and arginine) and is calculated to have a secondary structure that is 30% helical. The corresponding transcript is initiated approximately 50 nucleotides prior to the presumed initiation codon. Insertion of an Escherichia coli lacZ gene fragment into the putative HO coding segment inactivated HO and formed a hybrid HO-lacZ gene whose beta-galactosidase activity was regulated by the mating type locus in the same manner as HO (repressed by a 1-alpha 2). Upstream regions of 1,360 and 762 bp conferred strong repression; 436 bp led to partial constitutivity and 301 bp to full constitutivity. Thus, DNA sequences that confer repression of HO by a1-alpha 2 are at least 250 nucleotides upstream of the transcription start point and are within 436 nucleotides of the HO initiation codon. The progressive loss of repression suggests that both the -762 to -436 and the -436 to -301 intervals contain sites for regulation by a1-alpha 2. The HO gene contains two distinct regions that promote autonomous replication of plasmids in S. cerevisiae. These regions contain sequences that are homologous to the two conserved sequences that are associated with ARS activity.

A CIS-ACTING MUTATION WITHIN THE MAT  a LOCUS OF SACCHAROMYCES CEREVISIAE THAT PREVENTS EFFICIENT HOMOTHALLIC MATING-TYPE SWITCHING

Genetics ◽  
1980 ◽  
Vol 94 (2) ◽  
pp. 341-360
Author(s):  
Deborah Wygal Mascioli ◽  
James E Haber
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mating Type ◽  
Pleiotropic Effect ◽  
Wild Type ◽  
Dominant Mutation ◽  
Cis Acting ◽  
Silent Genes ◽  
Factor Expression ◽  
Mating Type Switching ◽  
Ho Gene

ABSTRACT Homothallic strains of Saccharomyces cerevisiae are able to switch from one mating-type to the other as frequently as every cell division. We have identified a cis-dominant mutation of the MATa locus, designated MATa-inc, that can be converted to MATα at only about 5% of the normal efficiency. In homothallic MATa-inc/mata* diploids, the MATa-inc locus switched to MATα in only one of 30 cases, while the mata* locus switched to MATα in all 30 cases. The MATa-inc mutation can be "healed" by a series of switches, first to MATα and then to a normal allele of MATa. These data are consistent with the "cassette" model of HICKS, STRATHERN and HERSKOWITZ (1977), in which mating conversions involve the transposition of wild-type copies of a or α information from silent genes elsewhere in the genome. The MATa-inc mutation appears to alter a DNA sequence necessary for the replacement of MATa by MATα. The MATa-inc mutation has no other effect on MATa functions. In heterothallic backgrounds, the mutation has no effect on the sensitivity to α-factor, synthesis of a-factor, expression of barrier phenotype or ability to mate or sporulate.—The MATa-inc allele does, however, exhibit one pleiotropic effect. About 1% of homothallic MATa-inc cells become completely unable to switch mating type because ofmutations at HMa, the locus proposed to carry the silent copy of α information.—In addition, we have isolated a less efficient allele of the HO gene.

scholarly journals Structure of the Saccharomyces cerevisiae HO gene and analysis of its upstream regulatory region.

1986 ◽  
Vol 6 (12) ◽  
pp. 4281-4294 ◽  
Author(s):  
D W Russell ◽  
R Jensen ◽  
M J Zoller ◽  
J Burke ◽  
B Errede ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mating Type ◽  
Dna Sequences ◽  
Regulatory Region ◽  
Initiation Codon ◽  
Upstream Region ◽  
Lacz Gene ◽  
Type Locus ◽  
Reading Frame ◽  
Ho Gene

The HO gene product of Saccharomyces cerevisiae is a site-specific endonuclease that initiates mating type interconversion. We have determined the nucleotide sequence of a 3,129-base-pair (bp) segment containing HO. The segment contains a single long open reading frame encoding a polypeptide of 586 amino acids, which has unusual (unbiased) codon usage and is preceded by 762 bp of upstream region. The predicted HO protein is basic (16% lysine and arginine) and is calculated to have a secondary structure that is 30% helical. The corresponding transcript is initiated approximately 50 nucleotides prior to the presumed initiation codon. Insertion of an Escherichia coli lacZ gene fragment into the putative HO coding segment inactivated HO and formed a hybrid HO-lacZ gene whose beta-galactosidase activity was regulated by the mating type locus in the same manner as HO (repressed by a 1-alpha 2). Upstream regions of 1,360 and 762 bp conferred strong repression; 436 bp led to partial constitutivity and 301 bp to full constitutivity. Thus, DNA sequences that confer repression of HO by a1-alpha 2 are at least 250 nucleotides upstream of the transcription start point and are within 436 nucleotides of the HO initiation codon. The progressive loss of repression suggests that both the -762 to -436 and the -436 to -301 intervals contain sites for regulation by a1-alpha 2. The HO gene contains two distinct regions that promote autonomous replication of plasmids in S. cerevisiae. These regions contain sequences that are homologous to the two conserved sequences that are associated with ARS activity.

scholarly journals INTERCONVERSION OF YEAST MATING TYPES III. ACTION OF THE HOMOTHALLISM (HO) GENE IN CELLS HOMOZYGOUS FOR THE MATING TYPE LOCUS

Genetics ◽  
1977 ◽  
Vol 85 (3) ◽  
pp. 395-405 ◽  
Author(s):  
James B Hicks ◽  
Jeffrey N Strathern ◽  
Ira Herskowitz
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Life Cycle ◽  
Gene Product ◽  
Direct Observation ◽  
Mating Type ◽  
Mating Types ◽  
Type Locus ◽  
Mating Type Locus ◽  
Mating Type Switching ◽  
Ho Gene

ABSTRACT Mating type interconversion in homothallic Saccharomyces cerevisiae has been studied in diploids homozygous for the mating type locus produced by sporulation of a/a/a/α and a/a/α/α tetraploid strains. Mating type switches have been analyzed by techniques including direct observation of cells for changes in α-factor sensitivity. Another method of following mating type switching exploits the observation that a/α cells exhibit polar budding and a/a and α/α cells exhibit medial budding.—These studies indicate the following: (1) The allele conferring the homothallic life cycle (HO) is dominant to the allele conferring the heterothallic life cycle (ho). (2) The action of the HO gene is controlled by the mating type locus—active in a/a and α/α cells but not in a/α cells. (3) The HO (or HO-controlled) gene product can act independently on two mating type alleles located on separate chromosomes in the same nucleus. (4) A switch in mating type is observed in pairs of cells, each of which has the same change.

The Association between Silent Mating Type Information Regulator 2 Homolog 1 (SIRT1) Gene Polymorphism and Systemic Lupus Erythromatosis (SLE)

QJM ◽  
2021 ◽  
Vol 114 (Supplement_1) ◽  
Author(s):  
Abeer Ibrahim Abdel Megid ◽  
Manal Mohsen M Kamal El-Din ◽  
Nashwa Aly Morshedy ◽  
Walaa Ahmed Yousry Kabiel ◽  
Sarah Abdel Mohsen Ismail
Keyword(s):  
Systemic Lupus Erythematosus ◽  
Lupus Nephritis ◽  
Gene Polymorphism ◽  
Disease Activity ◽  
Mating Type ◽  
Lupus Erythematosus ◽  
Systemic Lupus ◽  
Significant Difference ◽  
Sirt1 Gene ◽  
Type Information

ABSTRACT Background Systemic lupus erythematosus (SLE) is a chronic severe multisystem autoimmune disease that affects multiple organs being characterized by heterogeneous manifestations that may affect the skin, joint, heart, brain, kidney, hematopoietic and central nervous systems. It is characterized by autoantibody production for a variety of self-antigens, but it is specifically associated with anti-double stranded DNA (anti-dsDNA), and immune complex deposition. The Silent Mating Type Information Regulator 2 Homolog 1 (SIRT1) is a NAD-dependent deacetylase enzyme that plays an important role in regulating a variety of cellular processes, such as energy metabolism, cell-cycle progression, apoptosis, aging, immune system regulation and inflammation. Aim of the Work The aim of the present study is to investigate the association of SIRT1 rs3758391 gene polymorphism with SLE and to study its impact on disease progression to lupus nephritis. Subjects and Methods This is a case control study conducted at Ain Shams University Hospital, with a total of 50 participants including 34 patients diagnosed with SLE in addition to 16 age and sex matched individuals serving as a healthy control group. Results The results revealed no significant difference between the SLE patients and the controls as regards CC, CT and TT genotypes, yet there was a statistical significant difference between both groups as regards the C and T alleles. Conclusion The present study highlights that SIRT1 gene rs3753891 does not seem to influence lupus nephritis susceptibility and disease activity as indicated by Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) scoring. However, T allele may be a risk factor for lupus susceptibility.

Physical monitoring of mating type switching in Saccharomyces cerevisiae

1988 ◽  
Vol 8 (6) ◽  
pp. 2342-2349 ◽  
Author(s):  
B Connolly ◽  
C I White ◽  
J E Haber
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Mating Type ◽  
G1 Phase ◽  
Opposite Mating Type ◽  
Synthesis Inhibitor ◽  
Mating Type Switching ◽  
G2 Phase ◽  
Kinetics Of ◽  
Ho Gene

The kinetics of mating type switching in Saccharomyces cerevisiae can be followed at the DNA level by using a galactose-inducible HO (GAL-HO) gene to initiate the event in synchronously growing cells. From the time that HO endonuclease cleaves MAT a until the detection of MAT alpha DNA took 60 min. When unbudded G1-phase cells were induced, switched to the opposite mating type in "pairs." In the presence of the DNA synthesis inhibitor hydroxyurea, HO-induced cleavage occurred but cells failed to complete switching. In these blocked cells, the HO-cut ends of MATa remained stable for at least 3 h. Upon removal of hydroxyurea, the cells completed the switch in approximately 1 h. The same kinetics of MAT switching were also seen in asynchronous cultures and when synchronously growing cells were induced at different times of the cell cycle. Thus, the only restriction that confined normal homothallic switching to the G1 phase of the cell cycle was the expression of HO endonuclease. Further evidence that galactose-induced cells can switch in the G2 phase of the cell cycle was the observation that these cells did not always switch in pairs. This suggests that two chromatids, both cleaved with HO endonuclease, can interact independently with the donors HML alpha and HMRa.

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