The HOP1 gene encodes a meiosis-specific component of yeast chromosomes.

The HOP1 gene in Saccharomyces cerevisiae is important for meiotic chromosomal pairing, because hop1 diploids fail to form synaptonemal complex during meiosis and are defective in crossing over between, but not within, chromosomes. We demonstrate here that the HOP1 gene is transcriptionally regulated during sporulation and that the HOP1 protein is situated along the lengths of meiotic chromosomes. Furthermore, the HOP1 protein contains a Cys2/Cys2 zinc finger motif. A mutation within this motif that changes a cysteine to serine results in the hop1 phenotype, consistent with the possibility that the HOP1 gene product acts in chromosome synapsis by directly interacting with DNA. These observations demonstrate that HOP1 encodes a component of meiotic chromosomes, perhaps serving as a constituent of the synaptonemal complex.