RESUMO
Meiosis is a specialized cell division for producing haploid gametes from diploid germ cells. During meiosis, synaptonemal complex (SC) mediates the alignment of homologs and plays essential roles in homologous recombination and therefore in promoting accurate chromosome segregation. In this study, we have identified a novel protein SCRE (synaptonemal complex reinforcing element) as a key molecule in maintaining the integrity of SC during meiosis prophase I in mice. Deletion of Scre (synaptonemal complex reinforcing element) caused germ cell death in both male and female mice, resulting in infertility. Our mechanistic studies showed that the synapses and SCs in Scre knockout mice were unstable due to the lack of the SC reinforcing function of SCRE, which is sparsely localized as discrete foci along the central elements in normal synaptic homologous chromosomes. The lack of Scre leads to meiosis collapse at the late zygotene stage. We further showed that SCRE interacts with synaptonemal complex protein 1 (SYCP1) and synaptonemal complex central element 3 (SYCE3). We conclude that the function of SCRE is to reinforce the integrity of the central elements, thereby stabilizing the SC and ensuring meiotic cell cycle progression. Our study identified SCRE as a novel SC fastener protein that is distinct from other known SC proteins.
Assuntos
Proteínas de Ciclo Celular/fisiologia , Prófase Meiótica I , Proteínas Nucleares/fisiologia , Complexo Sinaptonêmico/fisiologia , Animais , Sistemas CRISPR-Cas , Segregação de Cromossomos , Proteínas de Ligação a DNA , Feminino , Células HEK293 , Humanos , Masculino , Meiose , Camundongos , Camundongos Knockout , Proteínas Nucleares/genética , Ligação Proteica , Recombinação Genética , Espermatócitos/metabolismo , Testículo/metabolismoRESUMO
Rad21/Rec8 is an important component and key regulator of cohesins. A RAD21-like gene from rice (Oryza sativa L. ssp. japonica) has been cloned and termed OsRAD21-1. OsRAD21-1 is a single-copy gene in the rice genome and is expressed in the entire plant. OsRad21-1 consists of 1055 amino acid residues and is the largest of the Rad21/Rec8 family identified to date. Based on sequence similarity comparison with other members of this family and gene expression patterns, it is concluded that OsRad21 is a rice orthologue of yeast Rad21.