High impact information on BUD3

• Here we report a physical association of promoter and terminator regions of the yeast BUD3 and SEN1 genes [1].
• Genetic analysis indicates that AXL2 falls into the same epistasis group as BUD3 [2].
• BUD3 is expressed close to the onset of mitosis [3].
• Two other bud site selection genes, RSR1, encoding a small GTPase, and BUD3, were also required for efficient cell fusion [4].
• Mutations in BUD3, BUD4, and AXL1 cause a and alpha cells to exhibit the bipolar pattern, indicating that these genes are necessary to specify the axial budding pattern (Chant, J., and I. Herskowitz. 1991. Cell. 65:1203-1212; Fujita, A., C. Oka, Y. Arikawa, T. Katagi, A. Tonouchi, S. Kuhara, and Y. Misumi. 1994. Nature (Lond.). 372:567-570) [5].

Biological context of BUD3

• These observations suggest that Bud4p and Bud3p cooperate to recognize a spatial landmark (the neck filaments) during mitosis and support the hypothesis that they subsequently become a landmark for establishing the axial budding pattern in G1 [5].
• Taken together, the data suggest that Bud3p and the neck filaments are linked in a cycle in which each controls the position of the other's assembly: Bud3p assembles onto the neck filaments in one cell cycle to mark the site for axial budding (including assembly of the new ring of neck filaments) in the next cell cycle [6].
• In the axial budding pattern, cells polarize and divide adjacent to the previous site of cell separation, in response to a cell-division remnant, which includes Bud3p, Bud4p and septin proteins [7].
• These include: an obscure subfamily of globins in the roundworm Caenorhabditis elegans ; two new superfamilies of metallohydrolases; a lipoyl/biotin swinging arm domain in bacterial membrane fusion proteins; and a DH domain in the yeast Bud3 and Fus2 proteins [8].
• Mutants defective in bipolar budding were identified by virtue of their inability to grow as pseudohyphae in a haploid bud3 background [9].

Anatomical context of BUD3

• Clusters of Bud10p at the mother-bud neck formed in response to Bud3p (and possibly to an extracellular cue, such as a component of the cell wall), might facilitate the docking of downstream components that direct polarization of the cytoskeleton [7].

Co-localisations of BUD3

• Clb2 co-localizes with the bud site selection protein Bud3 [10].

Other interactions of BUD3

• Upon shift of a temperature-sensitive cdc12 mutant to restrictive temperature, localization of both Bud3p and the neck filament-associated proteins is rapidly lost [6].
• The Bud3p structure at the neck persists until cytokinesis, when it splits to yield a single ring of Bud3p marking the division site on each of the two progeny cells [6].

Analytical, diagnostic and therapeutic context of BUD3

• However, immunofluorescence localization of Bud3p has revealed that it assembles in an apparent double ring encircling the mother-bud neck shortly after the mitotic spindle forms [6].

References