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The cohesin complex: sequence homologies, interaction networks and shared motifs
1Computational Genome Analysis Laboratory, Imperial Cancer Research Fund, 44 Lincoln's Inn Fields, London, WC2A 3PX, UK. Susan.Jones@icrf.icnet.uk
Genome Biology
|March 29, 2001
Summary
Researchers identified new structural maintenance of chromosomes (SMC) protein homologs and built a cohesion interaction network. This advances understanding of cohesin complex function in sister-chromatid cohesion.
Area of Science:
- Molecular Biology
- Genomics
- Proteomics
Background:
- Cohesin is a crucial macromolecular complex responsible for linking sister chromatids during mitosis.
- This complex, including structural maintenance of chromosomes (SMC) and sister-chromatid cohesion (SCC) proteins, plays a vital role from DNA replication to the metaphase-to-anaphase transition.
- The precise functions of individual cohesin proteins remain largely unelucidated.
Purpose of the Study:
- To investigate and identify novel homologs of cohesin proteins using genomic and proteomic data.
- To construct a comprehensive cohesion interaction network to better understand cohesin complex function.
- To explore potential regulatory mechanisms, such as phosphorylation, involved in sister-chromatid cohesion.
Main Methods:
- Searched protein sequence databases to identify new cohesin protein homologs.
- Constructed a cohesion interaction network utilizing two proteomic databases.
- Analyzed gene upstream regions for common regulatory elements (e.g., MluI cell-cycle box) and identified shared protein sequence motifs.
Main Results:
- Identified new structural maintenance of chromosomes (SMC) homologs, including Mmip1 in mouse, which shares high sequence identity with Smc3.
- Established a phylogenetic tree of SMC homologs, revealing five distinct families.
- Developed a cohesion interaction network of 17 proteins, noting shared upstream regulatory elements and sequence motifs among interacting proteins. Scc2 shares a motif with Chk1, suggesting potential kinase activity.
Conclusions:
- The integration of genomic and proteomic data provides a comprehensive network for understanding cohesin function.
- The identification of new SMC homologs and conserved motifs offers insights into protein structure and interactions.
- The potential kinase activity of Scc2 presents a testable hypothesis for phosphorylation-based regulation of sister-chromatid cohesion.