Chun So, Ph.D.

Assistant Investigator, NIBS, Beijing

Email: sochun@nibs.ac.cn

Education

2019 Dr. rer. nat. (summa cum laude) in Biology (Physics of Biological and Complex Systems), Georg-August-Universität Göttingen, Göttingen, Germany

Professional Experience

2022 – Present Assistant Investigator, National Institute of Biological Sciences, Beijing, China

Research Description

Focusing on female reproductive health is a key way of dealing with population aging. Abnormal egg and embryo development are the leading causes of female infertility, miscarriage and genetic disorders such as Down Syndrome. Previously we have made several pioneering discoveries of the mechanisms underlying meiotic maturation of oocytes into eggs, such as the biophysical mechanism underlying spindle assembly in mammalian oocytes and the molecular mechanism underlying spindle instability and chromosome missegregation in human oocytes.

First, we discovered how mammalian oocytes utilize centrosomal proteins to assemble acentrosomal spindles (So and Seres et al. Science 2019). Mammalian oocytes express many centrosomal proteins despite the absence of centrosomes. During female meiosis, some of these proteins undergo a biophysical phenomenon known as liquid-liquid phase separation to form a previously undescribed domain, which we termed the liquid-like meiotic spindle domain (LISD). The LISD sequesters and mobilizes centrosomal proteins with microtubule regulatory functions in proximity to spindle microtubules, thus promoting spindle assembly in the absence of centrosomes.

Second, we uncovered how are spindle poles organized and why are they unstable in human oocytes (So et al. Science 2022). Human and other mammalian oocytes similarly utilize NUMA to recruit dynein to microtubule minus-ends for the focusing of acentrosomal spindle poles. However, unlike human oocytes, other mammalian oocytes do not assemble unstable spindles. Using a reverse genetic screen, we identified the minus-end-directed kinesin KIFC1 as a key determinant of meiotic spindle stability. While KIFC1 is readily expressed in most mammalian oocytes, it is deficient in human oocytes. By introducing exogenous KIFC1, we successfully increased the fidelity of spindle assembly and chromosome segregation in human oocytes. For the first time, we proposed a potential therapeutic method for reducing the risk of aneuploidy in human eggs.

With our expertise in cutting-edge light and electron microscopy and the support from the 13 core facilities at NIBS, we will continue adopting a cross-disciplinary approach to illuminate novel cellular, molecular and biophysical mechanisms underlying egg and embryo development across different mammalian models.. Our findings will provide novel insights into the causes and treatments of female infertility, and improve the existing assisted reproductive technologies.

(*Equal contribution)

10. So, C., Menelaou, M., Uraji, J., Harasimov, K., Steyer, A.M., Seres, K.B., Bucevičius, J., Lukinavičius, G., Möbius, W., Sibold, C., Tandler-Schneider, A., Eckel, H., Moltrecht, R., Blayney, M., Elder, K., Schuh, M. “Mechanism of spindle pole organization and instability in human oocytes” Science (2022); Feb; 375(6581):eabj3944

- Covered by Nat. Cell Biol. in “Spindle instability in human oocytes”

- Highlighted by J. Assist. Reprod. Genet. in “Failure to focus seems to be a hominid thing”

9. So, C.*, Cheng, S.*, Schuh, M. “Phase separation during germline development” Trends Cell Biol. (2021); Apr; 31(4):254-268

8. Chan, Y.W.*, So, C.*, Yau, K.L., Chiu, K.C., Wang, X., Chan, F.L., Tsang, S.Y. “Adipose-derived stem cells and cancer cells fuse to generate cancer stem cell-like cells with increased tumorigenicity” J. Cell Physiol. (2020); Oct; 235(10):6794-6807

7. So, C.*, Seres, K.B.*, Steyer, A.M., Mönnich, E., Clift, D., Pejkovska, A., Möbius, W., Schuh, M. “A liquid-like spindle domain promotes acentrosomal spindle assembly in mammalian oocytes” Science (2019); Jun; 364(6447):eaat9557

- Recommended by F1000Prime

- Highlighted by J. Assist. Reprod. Genet. in “Phase transitions in human ARTs: fertility preservation comes of age”

6. Xu, Y., So, C., Lam, H.M., Fung, M.C., Tsang, S.Y. “Flow cytometric detection of newly-formed breast cancer stem cell-like cells after apoptosis reversal” J. Vis. Exp. (2019); Jan; (143)

5. Clift, D.*, So, C.*, McEwan, W.A., James, L.C., Schuh, M. “Acute and rapid degradation of endogenous proteins by Trim-Away” Nat. Protoc. (2018); Oct; 13(10):2149-2175

4. Xu, Y., So, C., Lam, H.M., Fung, M.C., Tsang, S.Y. “Apoptosis reversal promotes cancer stem cell-like cell formation” Neoplasia (2018); Mar; 20(3):295-303

3. Yang, H., Buisson, S., Bossi, G., Wallace, Z., Hancock, G., So, C., Asfield, R., Vuidepot, A., Mahon, T., Molloy, P., Oates, J., Paston, S.J., Aleksic, M., Hassan, N.J., Jakobsen, B.K., Dorrell, L. “Elimination of latently HIV-infected cells from antiretroviral therapy-suppressed subjects by engineered immune-mobilizing T-cell receptors” Mol. Ther. (2016); Nov; 24(11):1913-1925

2. Lo, I.C., Chan, H.C., Qi, Z., Ng, K.L., So, C., Tsang, S.Y. “TRPV3 channel negatively regulates cell cycle progression and safeguards the pluripotency of embryonic stem cells” J. Cell Physiol. (2016); Feb; 231(2):403-413

1. Qi, Y., Qi, Z., Li, Z., Wong, C.K., So, C., Lo, I.C., Huang, Y., Yao, X., Tsang, S.Y. “Role of TRPV1 in the differentiation of mouse embryonic stem cells into cardiomyocytes” PLoS One (2015); Jul; 10(7):e0133211