High impact information on SGA1

• Gph1p and Sga1p may therefore degrade physically distinct pools of glycogen [1].
• STA1 mRNA was induced in diploids during sporulation along with SGA, a closely linked gene that encodes an intracellular sporulation-specific glucoamylase of S. cerevisiae [2].
• Leaky expression was eliminated using 3-aminotriazole and gene conversion was eliminated by using the Schizosaccharomyces pombe his5+ gene, resulting in a 5- to 10-fold improvement in the efficiency of SGA [3].
• Using a genetic array of nonessential null mutations (SGA) we identified mutations that are sick/lethal in combination with the rsc7delta mutation, which revealed connections to a surprisingly large number of chromatin remodeling complexes and cellular processes [4].
• These genes are absent in S. cerevisiae, but a related gene, SGA1, encoding an intracellular, sporulation-specific glucoamylase (SGA), is present [5].

Biological context of SGA1

• The S1, S2 and SGA1 ancestral genes for the STA glucoamylase genes all map to chromosome IX in Saccharomyces cerevisiae [6].
• To study the role of sequences upstream of the SGA1 gene in its expression and regulation, we generated internal deletions in the 5' non-coding region of the gene and chimeric genes with portions of the upstream sequence inserted into a reporter gene [7].
• A sporulation-specific glucoamylase gene called SGA1 exists in every Saccharomyces cerevisiae strain, this also having a partly homologous DNA sequence with the STA genes [8].
• These data and RNA blot analysis revealed that the following regions of STA1 were highly conserved in S2, S1, and SGA: upstream regulatory sequences responsible for transcription, a signal sequence for protein secretion, a threonine- and serine-rich domain, and a catalytic domain for glucoamylase activity [9].
• This finding was re-examined by determining the effects of STA10 on the expression of gene constructs containing different fragments from the SGA and STA2 promoter regions fused to the lacZ gene [10].

Regulatory relationships of SGA1

• SGA was expressed in vegetatively growing cells under the control of the GAL1 promoter, and the cellular location of the enzymatic activity determined by fractionation techniques [11].

Other interactions of SGA1

• The SGA1 sporulation-specific, intracellular glucoamylase-encoding gene is located on the left arm of chromosome IX, 32 kb proximal of HIS5 [6].
• STA1 induction may be a response to the starvation conditions necessary for sporulation, while SGA induction is governed by the pathway by which MAT regulates sporulation [2].
• SGA was preferentially recovered in fractions which were enriched for the vacuolar hydrolases, carboxypeptidase Y and alpha-mannosidase [11].

References