Nuclear peripheral chromatin-lamin B1 interaction is required for global integrity of chromatin architecture and dynamics in human cells

The eukaryotic genome is folded into higher-order conformation accompanied with constrained dynamics for coordinated genome functions. However, the molecular machinery underlying these hierarchically organized three-dimensional (3D) chromatin architecture and dynamics remains poorly understood. Here by combining imaging and sequencing, we studied the role of lamin B1 in chromatin architecture and dynamics. We found that lamin B1 depletion leads to detachment of lamina-associated domains (LADs) from the nuclear periphery accompanied with global chromatin redistribution and decompaction. Consequently, the inter-chromosomal as well as inter-compartment interactions are increased, but the structure of topologically associating domains (TADs) is not affected. Using live-cell genomic loci tracking, we further proved that depletion of lamin B1 leads to increased chromatin dynamics, owing to chromatin decompaction and redistribution toward nucleoplasm. Taken together, our data suggest that lamin B1 and chromatin interactions at the nuclear periphery promote LAD maintenance, chromatin compaction, genomic compartmentalization into chromosome territories and A/B compartments and confine chromatin dynamics, supporting their crucial roles in chromatin higher-order structure and chromatin dynamics.

Direct cloning of the newest angiogenesis inhibitor,arresten / 重庆医科大学学报

Objective:To clone and express the new angiogenesis inhibitor,arresten.Methods:The total RNA was extracted from the normal human liver,and then was reversely transcribed mRNA to cDNA and arresten cDNA was amplified by nestle-PCR.After being treated by T4 DNA polymerase,the arresten cDNA was linked with the linear vector pTYB1 digested by NdeI and EcoRI.And then the complete ER2566 was transfected by recombinant vector,the recombination was screened and the expression of the interest protein was induced by IPTG.Results:The arresten was cloned by one-step cloning method with PCR product treated by T4 DNA polymerase.Conclusion:This method can be used to clone the interest gene more easily and quickly than T-A clone and others.