Meiosis-specific yeast Hop1 protein promotes pairing of double-stranded DNA helices via G/C isochores.
In eukaryotes, genetic exchange between homologs is facilitated by a tripartite proteinaceous structure called the synaptonemal complex (SC). Several lines of evidence indicate that the genes that encode components of SC are essential for meiotic chromosome pairing and recombination. However, the molecular mechanism by which SC proteins promote these processes is obscure. Here, we report that Saccharomyces cerevisiae Hop1 protein, a component of SC, promotes pairing between two double-stranded DNA helices containing a centrally located G/C isochore. Significantly, pairing was rapid and robust, and required four contiguous G/C base pairs. Using a series of truncated DNA double helices we show that 20 bp on either side of 8 bp target G/C sequence is essential for pairing. To our knowledge, Hop1 is the first protein shown to do so from yeast or any other organism. These results indicate that Hop1 protein is likely to play a direct role in meiotic chromosome pairing and recombination.
Anuradha
S
S
Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India.
Tripathi
Pankaj
P
Mahajan
Kiran
K
Muniyappa
K
K
D020029:Base Pairing; D001483:Base Sequence; D023902:Chromosome Pairing; D003596:Cytosine / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D006147:Guanine / Q000737:chemistry*; D032085:Isochores; D007700:Kinetics; D008540:Meiosis; D008969:Molecular Sequence Data; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*
D004268:DNA-Binding Proteins; C086672:HOP1 protein, S cerevisiae; D032085:Isochores; D029701:Saccharomyces cerevisiae Proteins; D006147:Guanine; D003596:Cytosine; D004247:DNA