39HIGHLIGHTS 2020

AtFKBP53: a chimeric histone chaperone with functional nucleoplasmin and PPIase domains, A.K. Singh (a,b), A. Datta (a), C. Jobichen (c), S. Luan (d) and D. Vasudevan (a), Nucleic Acids Res. 48(3), 1531-1550 (2020); https://doi.

org/10.1093/nar/gkz1153. Figures adapted from the original publication. (a) Institute of Life Sciences (ILS), Bhubaneswar (India) (b) Manipal Academy of Higher Education (MAHE), Manipal (India)

(c) Department of Biological Sciences (DBS), National University of Singapore (NUS) (Singapore) (d) Department of Plant and Microbial Biology, University of California, Berkeley (USA)

[1] C. Edlich-Muth et al., J. Mol. Biol. 427, 1949-1963 (2015). [2] H. Li & S. Luan, Cell Res. 20, 357-366 (2010).

STRUCTURAL INSIGHTS INTO GENOME FOLDING BY COHESIN-CTCF

Cohesin and CTCF are key regulators for 3D genome folding. A crystal structure of CTCF bound to a cohesin subcomplex reveals a key binding interface. Analysis in cells shows that the interaction between CTCF and cohesin is required for large-scale genome organisation.

PRINCIPAL PUBLICATION AND AUTHORS

REFERENCES

Human genomic DNA, if it were stretched out, would reach over two metres in length, but in a cell, DNA needs to be compacted into a micron- sized nucleus. Higher-order genome folding is mediated by structural maintenance of chromosomes (SMC) proteins, an ancient class of ATPases found in all domains of life. SMC proteins are large, ring-shaped proteins that act by DNA loop extrusion, organising DNA into large, dynamic loops. One of the most exciting

challenges today is to understand how DNA looping contributes to the most fundamental aspects of genome biology. Gene regulation requires interaction between distant regulatory elements, which DNA looping can both facilitate or prevent, contributing to determining which genes are activated. Loop extrusion may also contribute to other aspects of genome regulation, preventing genome entanglement and allowing processes that act on DNA, such

Fig. 25: a) Schematic depiction of a Hi-C matrix displaying two TADs (red squares). TADs are flanked by pairs of convergently oriented CTCF sites (arrows). The contacts within a TAD are formed by cohesin complexes (blue circles). Cohesin builds loops that it can enlarge until it encounters CTCF to form TAD corner peaks . b) Cartoon of the structure of the cohesin complex. c,d) Structure of the SA2-SCC1- CTCF complex.