In the beginning: the initiation of meiosis

Abstract

The most-critical point of reproductive development in all sexually reproducing species is the transition from mitotic to meiotic cell cycle. Studies in unicellular fungi have indicated that the decision to enter meiosis must be made before the beginning of the premeiotic S phase. Recent data from the mouse suggest that this timing of meiosis initiation is a universal feature shared also by multicellular eukaryotes. In contrast, the signaling cascade that leads to meiosis initiation shows great diversity among species.

Cdk3, a conjugation-specific cyclin-dependent kinase, is essential for the initiation of meiosis in Tetrahymena thermophila

“…In the absence of either of these proteins, conjugation was arrested at the pair formation stage and early meiotic events (DSB formation, MIC elongation, and DSB repair) did not occur. These results are consistent with previous studies in yeast, 1,17 suggesting that the mechanism controlling Cdk and cyclin function in meiosis initiation may be conserved among species.…”

“…Although all of these events are conserved among species, diverse mechanisms control meiosis initiation. 1,2 In Saccharomyces cerevisiae, starvation induces expression of IME1, which encodes a transcription factor that transactivates early meiotic genes. 3 One of the target genes, IME2, encodes the meiosis induction protein kinase (Ime2), which promotes meiotic DNA replication.…”

OsAM1 is required for leptotene-zygotene transition in rice

“…In multicellular organisms, meiosis occurs in cells that are already destined to become meiocytes, and the switch from mitosis to meiosis is also under genetic control. In mammals, mouse STRA8 regulates retinoic acid signaling, which has the ability to induce meiosis, and germ cells of the STRA8-knockout mouse arrest before pre-meiotic S phase [19]. The isolation of two genes, SWI1 (SWITCH1) in Arabidopsis and its homolog, AM1 (AMEIOTIC1) in maize, has shed more light on this question in plants.…”

Investigating Host Induced Meiosis in a Fungal Plant Pathogen

“…Therefore, it is essential that entry into meiosis is tightly controlled, preventing the inappropriate execution of the meiotic program. The signals that trigger meiosis vary extensively between organisms, possibly due to a need for organisms to respond to the unique environmental niches in which they reside (Pawlowski et al, 2007). While the signals that trigger meiosis initiation are different, the timing is conserved from yeast to mice, occurring prior to the premeiotic S phase (Pawlowski et al, 2007).…”

“…The signals that trigger meiosis vary extensively between organisms, possibly due to a need for organisms to respond to the unique environmental niches in which they reside (Pawlowski et al, 2007). While the signals that trigger meiosis initiation are different, the timing is conserved from yeast to mice, occurring prior to the premeiotic S phase (Pawlowski et al, 2007). While this may seem obvious, the complex developmental processes that precede and accompany meiosis have obscured the timing until recently (Pawlowski et al, 2007).…”