Initiation of meiosis and sporulation in Saccharomyces cerevisiae requires a novel protein kinase homologue

Abstract

SME1 was cloned due to its high copy number effect: it enabled MATa/MAT alpha diploid cells to undergo meiosis and sporulation in a vegetative medium. Disruption of SME1 resulted in a recessive Spo- phenotype. These results suggest that SME1 is a positive regulator for meiosis. DNA sequencing analysis revealed an open reading frame of 645 amino acids. An amino terminal peptide of ca 400 amino acids in the deduced protein was similar to known protein kinases. Transcription of SME1 was regulated negatively by nitrogen and glucose and positively by MATa/MAT alpha and IME1, another positive regulator gene of meiosis. By complementation analysis, SME1 was found to be identical to IME2, which had been shown to be important in meiosis. These results suggest that IME1 product stimulates meiosis by activating transcription of SME1 (IME2) and that protein phosphorylation is required for initiation of meiosis.

A transcriptional autoregulatory loop for KIN28–CCL1 and SRB10–SRB11, each encoding RNA polymerase II CTD kinase–cyclin pair, stimulates the meiotic development of S. cerevisiae

“…RNA blot analysis was carried out as described (Kawaguchi et al, 1992;Yoshida et al, 1990;Hayashi et al, 1998b), except using as probes a 0.45 kb EcoRI±HindIII fragment of CLN3, 1.23 kb AatI±SacII of SRB10, 0.59 kb BglII±HindIII of SRB11, 1.53 kb HindIII±BamHI of CCR4, 0.82 kb KIN28, 1.03 kb CCL1, 1.91 kb SSA4 and 0.65 kb CUP1. The fragments of KIN28, CCL1, SSA4, and CUP1 lie in open reading frames and were obtained through PCR ampli®cation with primer pairs as follows: KIN28 (5k-GTTGGTGAGGGTACTTAT-GC-3k and 5k-CTAAACACTGAACAGCGGTC-3k); CCL1 (5k-ACTCCTTCTGCTACCATGTC-3k and 5k-TCTTGGCCTCTTCAGTACTC-3k); SSA4 (5k-GGCCTATCTCTTCTTTCTCC-3k and 5k-AT-GGGGTTTGCAACACCTTC-3k); and CUP1 (5k-CTGTCAGTCACTGTCAAGAG-3k and 5k-ATT-CTTGGGGCGACATATGG-3k).…”

“…It also induces meiosis-speci®c genes called IME1 and IME2 (Hayashi et al, 1998b), which are speci®cally expressed early in the meiotic development and required for the entry into meiosis. IME1 activates transcription of IME2 (Smith and Mitchell, 1989;Yoshida et al, 1990), encoding the meiosis-speci®c protein kinase (Kominami et al, 1993), and both are required for premeiotic DNA synthesis and subsequent meiotic development (Mitchell, 1994). These results therefore indicate that yeast cells communicate with each other by producing carbon dioxide and elevating medium pH in order to undergo G 1 arrest and meiosis.…”

Nutritional Regulation of Meiosis-specific Gene Expression in Saccharomyces cerevisiae

“…,-----, ,.--, 1 2 3 4 5 and pSPI 5 ) contain IMEI and IME2, respectively, both carrying LEU2 and URA3.…”

“…One of the plasmids, pSPl, had been found to carry the fME2 (SMEl) gene, which encodes a novel protein kinase homologue. 5) We report here studies on the remaining two plasmids (pSP2 and pSP3). Restriction mapping analysis (described below) of the yeast inserts cloned on pSP2 and pSP3 found no similarity to IMEl,3) IME2, 4,5) or MCKl,14) and therefore represents new loci The a/a diploid cells (AMI205-9B x YIY344) were transformed with each plasmid (e, pSPI; ... , pSP2; ., pSP3; and 0, pYIl).…”

Nps1/Sth1p, a component of an essential chromatin‐remodeling complex of Saccharomyces cerevisiae, is required for the maximal expression of early meiotic genes

“…For this experiment we used an ime2-lacZ fusion gene (containing sequences ¹984 to þ117 of IME2 fused in-frame to E. coli lacZ ORF, Yoshida et al 1990) inserted in a high-copynumber vector (Fig. 3).…”