High impact information on AMA1

• The yeast APC/C subunit Mnd2 prevents premature sister chromatid separation triggered by the meiosis-specific APC/C-Ama1 [1].
• The meiosis-specific processing of AMA1 mRNA depends on the previously described MER1 splicing factor [2].
• Third, ectopic overexpression of AMA1 is able to stimulate ubiquitination of Clb1p in vitro and degradation of Clb1p in vivo [2].
• Mutants lacking AMA1 revealed that it is required for the first meiotic division but not the mitotic-like meiosis II [2].
• Here we describe the yeast gene AMA1, a new member of the Cdc20 protein family that regulates the multisubunit ubiquitin ligase termed the anaphase promoting complex/cyclosome (APC/C) [2].

Biological context of AMA1

• The requirement of Ama1p only for meiosis I and spore morphogenesis suggests a function for APC/C(Ama1) specifically adapted to germ cell development [2].
• In conclusion, this study indicates that Ama1p directs a meiotic APC/C that functions solely outside mitotic cell division [2].
• During S- and prophase, Mnd2 prevents activation of the APC/C by a meiosis-specific activator called Ama1 [1].
• The function of Ama1 in regulating Smk1 is independent of the FEAR network, which promotes exit from mitosis and exit from meiosis I through the Cdc14 phosphatase [3].
• To prevent nonnative glycosylation, a conservatively mutagenized PV66/AMA-1 gene (PV66Deltaglyc) lacking N-glycosylation sites was also developed [4].

Regulatory relationships of AMA1

• The Ama1-directed anaphase-promoting complex regulates the Smk1 mitogen-activated protein kinase during meiosis in yeast [3].

Other interactions of AMA1

• Second, Ama1p is required for the degradation of the B-type cyclin Clb1p, an APC/C substrate in both meiotic and mitotic cells [2].
• The data indicate that Cdc28 and Ama1 function in a pathway to trigger Smk1-dependent steps in spore morphogenesis [3].
• Here we show that Ama1, a meiosis-specific activator of the anaphase-promoting complex/cyclosome (APC/C), promotes Smk1 activation during meiosis [3].

References