Producing recombinant human chromobox protein homolog 7 (CBX7) in yeast involves several stages. Initially, the gene encoding the full-length CBX7 protein (1-251aa) is cloned into an expression vector and introduced into yeast cells. The cells are cultured under conditions that induce protein expression. Once sufficient growth is achieved, the cells are lysed to release the recombinant CBX7 protein, which is purified by affinity chromatography. Protein purity is assessed using SDS-PAGE, exceeding 90%.
The Human CBX7 protein, a member of the Polycomb group family, acts as a tumor suppressor in different types of cancers by inhibiting cell growth, inducing apoptosis, and regulating cell motility [1]. It downregulates the expression of the INK4a/ARF tumor suppressor locus, thereby extending the lifespan of normal human cells [2]. Studies have shown that CBX7 is involved in regulating gene expression, such as cyclin E, and interacts with other proteins like HMGA1b to modulate cell cycle progression and cancer development [3]. CBX7 can repress tumor suppressor loci independently of BMI-1 in lymphomagenesis [4].
Furthermore, the downregulation of CBX7 is associated with a more malignant phenotype in thyroid cancer and colon carcinomas, highlighting its significance as a potential biomarker for cancer prognosis [5][6]. In cervical cancer, decreased expression of CBX7 has been identified as an independent predictor of poor survival [7].
References:
[1] R. Li, Q. Yan, P. Tian, Y. Wang, J. Wang, T. Ninget al., Cbx7 inhibits cell growth and motility and induces apoptosis in cervical cancer cells, Molecular Therapy — Oncolytics, vol. 15, p. 108-116, 2019. https://doi.org/10.1016/j.omto.2019.09.002
[2] X. Zhang, L. Zhang, W. Qin, Y. Xiao, L. Zheng, X. Liuet al., Oncogenic role of the chromobox protein cbx7 in gastric cancer, Journal of Experimental & Clinical Cancer Research, vol. 29, no. 1, 2010. https://doi.org/10.1186/1756-9966-29-114
[3] R. Sepe, U. Formisano, A. Federico, F. Forzati, A. Bastos, D. Angeloet al., Cbx7 and hmga1b proteins act in opposite way on the regulation of the spp1 gene expression, Oncotarget, vol. 6, no. 5, p. 2680-2692, 2015. https://doi.org/10.18632/oncotarget.2777
[4] C. Scott, J. Gil, E. Hernando, J. Teruya‐Feldstein, M. Narita, D. Martínezet al., Role of the chromobox protein cbx7 in lymphomagenesis, Proceedings of the National Academy of Sciences, vol. 104, no. 13, p. 5389-5394, 2007. https://doi.org/10.1073/pnas.0608721104
[5] P. Pallante, A. Federico, M. Berlingieri, M. Bianco, A. Ferraro, F. Forzatiet al., Loss of the cbx7 gene expression correlates with a highly malignant phenotype in thyroid cancer, Cancer Research, vol. 68, no. 16, p. 6770-6778, 2008. https://doi.org/10.1158/0008-5472.can-08-0695
[6] X. Zheng, J. Zhou, B. Zhang, J. Zhang, J. Wilson, L. Guet al., Critical evaluation of cbx7 downregulation in primary colon carcinomas and its clinical significance in chinese patients, BMC Cancer, vol. 15, no. 1, 2015. https://doi.org/10.1186/s12885-015-1172-6
[7] L. An, J. Zhang, Z. Jin, Y. Xia, P. Wang, W. Ouyanget al., Decreased expression of cbx7 is an independent predictor of poor survival in cervical cancer,, 2021. https://doi.org/10.21203/rs.3.rs-371414/v1
