red1

Red1 is a meiosis-specific nuclear protein in the budding yeast Saccharomyces cerevisiae, encoded by the RED1 gene. It functions as a structural component of the meiotic chromosome axis and plays a key role in the formation of the synaptonemal complex and in regulating meiotic recombination.

During meiotic prophase I, Red1 localizes along the chromosome axis and contributes to the assembly of axial elements. It operates in concert with other axis factors such as Hop1 and Zip1 to promote proper chromosome pairing and synapsis. Red1 influences the distribution and frequency of crossovers, which are essential for accurate homologous chromosome segregation, and its absence leads to defects in recombination, impaired synapsis, and reduced spore viability.

In terms of structure, Red1 is described as a large coiled-coil protein that provides a scaffold along the chromosome axis. This scaffolding supports the alignment of homologous chromosomes and the coordination of recombination events during meiosis.

Expression of RED1 is tightly regulated and restricted to meiosis, aligning with the meiotic transcription program. Its function is conserved to varying degrees among fungal species, with homologs identified in multiple other yeasts, reflecting a broader role in meiotic chromosome organization within fungi.

Mutants lacking RED1 (red1Δ) are commonly used to study meiotic chromosome behavior, providing insight into the mechanisms of axis formation, synapsis, and crossover control.

See also: Synaptonemal complex, chromosome axis, Hop1, Zip1, meiotic recombination.