MEI1 , an Arabidopsis gene required for male meiosis: isolation and characterization

Abstract

The T-DNA tagged mutant gene of Arabidopsis thaliana, mei1, produces after meiosis an abnormal tetrad, consisting of five to eight microspores of varying sizes and DNA contents. Plant DNA flanking the inserted T-DNA was isolated by inverse PCR. An approximately 16-kb DNA fragment spanning the T-DNA insertion site was isolated by screening a wild-type genomic library, using the plant flanking DNA as a probe. Using RT-PCR and RNA isolated from very young flower buds, a cDNA fragment was obtained. Nucleotide sequence comparison of the cDNA and the genomic sequence in this region indicated a gene which contained two introns. The 5′ and 3′ splice sites of neither intron comply with the :GU...AG: rule. In the mutant, the T-DNA had inserted into one of the introns. The deduced sequence of the MEI1 wild-type gene, which contains 89 amino acids, shows possible similarity with the human acrosin-trypsin inhibitor, HUSI-II, and is about the same size. Two wildtype DNA fragments, both extending over the T-DNA insertion site, were introduced into mutant plants by Agrobacterium-mediated transformation and plants were selected for both hygromycin and kanamycin resistance. Several independent male-fertile transformants were obtained with one of the DNA fragments. The fragment showing complementation of the mutant phenotype indicated that the sequence with similarity to the acrosintrypsin inhibitor is MEI1. Within the 16-kb genomic fragment two other genes were identified; one showed no overall similarity to any protein sequence in the database and the other had almost complete identity with an Arabidopsis-transcribed sequence tag with similarity to ACC oxidase. Double mutants between mei1 and qrt1 were made, permitting better characterization of the mei1 phe-notype because the individual microspores continued to be held together after callose dissolution.

Genome-Wide Analysis of the Core DNA Replication Machinery in the Higher Plants Arabidopsis and Rice

“…This alignment supports the conclusion that like other ORC subunits, ORC6 is conserved in plants. Interestingly, our analysis indicates that the ORC6 C terminus is conserved Kosugi and Ohashi (2002);32, Toueille et al (2002);33, Castillo et al (2003); 34, Raynaud et al (2006);35, Furukawa et al (2003);36, Furukawa et al (2001);37, Jenik et al (2005); 38, Ronceret et al (2005); 39, He and Mascarenhas (1998);40, Yang and Sheila (2002); 41, Grelon et al (2003);42, Ishibashi et al (2001);43, Marwedel et al (2003);44, Ishibashi et al (2005); 45, Ishibashi et al (2006);46, Xia et al (2006); 47, Kimura et al (2003); 48, Kimura et al (2000b);49, Taylor et al (1998);50, Sunderland et al (2004); 51, Bonatto et al (2005); 52, Sunderland et al (2006).…”

A homologue of the yeast HOP1 gene is inactivated in the Arabidopsis meiotic mutant asy1

“…It has been reported that the Arabidopsis meiotic gene MEI1 (He and Mascarenhas 1998) contains introns that do not follow the GU...AG rule for intron splicing (Brown et al 1996). However, when the splice sites in ASY1 were examined all 21 introns were found to obey the rule, hence it is likely that the discrepancy is due to the software used to predict potential ORFs.…”

Using Crossover Breakpoints in Recombinant Inbred Lines to Identify Quantitative Trait Loci Controlling the Global Recombination Frequency

“…In Arabidopsis, the QTL on chromosome 1 in the Ler 3 Cvi population included the MEI1 gene (He and Mascarenhas 1998;Grelon et al 2003). A 9-kb region surrounding the gene MEI1 was sequenced in three distinct Arabidopsis lines (Col, Ler, and Cvi).…”