The Schizosaccharomyces pombe mei4⁺ Gene Encodes a Meiosis-Specific Transcription Factor Containing a forkhead DNA-Binding Domain

Abstract

The mei4؉ gene of the fission yeast Schizosaccharomyces pombe was cloned by functional complementation. The mei4 disruptant failed to complete meiosis-I but could proliferate normally. Meiosis is required for the formation of germ cells which transmit genetic information from generation to generation. This specialized nuclear division is characterized by a reduction in the chromosome number and frequent genetic recombination, both of which have contributed to the evolution of eukaryotes. Although meiosis has basically the same machinery, including spindles, centrosomes, and kinetochores, as mitosis in somatic cells, these two nuclear divisions are different in many aspects. Meiosis-specific gene products must be responsible for the various different features of meiosis, especially those of meiosis-I, such as the synapsis of homologous chromosomes, nondisjunction of sister chromatids, crossing over, and chiasmata formation.

Promoter-driven splicing regulation in fission yeast

“…We can observe a shift in the mobility of the probe in the presence of GSTMei4 and a supershift if we add a specific antibody (Fig. 12, left panel), with similar results to the ones obtained by C. Shimoda's group previously (Horie et al, 1998). A similar assay was performed with native extracts of wt and ∆mei4 strains at 4 hours of meiosis (Fig.…”

“…All of the have at least one FLEX motif in their promoters whose consensus seems to be longer (Fig. 21) that the one reported before (Horie et al, 1998). Although cis differences between FLEX motives with regulated and constitutive splicing could not be determined, future studies about chromatin structure and interaction of the Forkhead transcription factors between them and the DNA will give us more answers about it.…”

“…Although, previously a consensus FLEX box was described (Horie et al, 1998), Taking into account all these results we can conclude that the regulation of splicing is a general mechanism to control gene expression in meiosis. Figure 21.…”

“…Its expression is completely avoided in vegetative growing cells by specifically degradation of meiotic mRNAs by the mmi1 system (Harigaya et al, 2006). Mei4 has been reported to bind in vitro to the FLEX motif GTAAAYA (Horie et al, 1998).…”

“…1). These sequences are described to bind forkhead transcription factors in vivo (Horie et al, 1998). Since Mei4 is known to induce transcription and splicing of rem1 (Malapeira et al, 2005), we decided to mutate these FLEX boxes and study this modifications at the level of transcription and splicing.…”