Loss of Bmi1 causes anomalies in retinal development and degeneration of cone photoreceptors.

TitleLoss of Bmi1 causes anomalies in retinal development and degeneration of cone photoreceptors.
Publication TypeJournal Article
Year of Publication2016
AuteursBarabino, A, Plamondon, V, Abdouh, M, Chatoo, W, Flamier, A, Hanna, R, Zhou, S, Motoyama, N, Hébert, M, Lavoie, J, Bernier, G
Date Published2016 05 01
KeywordsAnimals, Cell Line, Checkpoint Kinase 2, Embryonic Stem Cells, Heterochromatin, Humans, Mice, Mice, Inbred C57BL, Mice, Knockout, Necrosis, Oxidative Stress, Polycomb Repressive Complex 1, Proto-Oncogene Proteins, Receptor-Interacting Protein Serine-Threonine Kinases, Retina, Retinal Cone Photoreceptor Cells, Retinal Rod Photoreceptor Cells, Tumor Suppressor Protein p53

Retinal development occurs through the sequential but overlapping generation of six types of neuronal cells and one glial cell type. Of these, rod and cone photoreceptors represent the functional unit of light detection and phototransduction and are frequently affected in retinal degenerative diseases. During mouse development, the Polycomb group protein Bmi1 is expressed in immature retinal progenitors and differentiated retinal neurons, including cones. We show here that Bmi1 is required to prevent post natal degeneration of cone photoreceptors and bipolar neurons and that inactivation of Chk2 or p53 could improve but not overcome cone degeneration in Bmi1(-/-) mice. The retinal phenotype of Bmi1(-/-) mice was also characterized by loss of heterochromatin, activation of tandem repeats, oxidative stress and Rip3-associated necroptosis. In the human retina, BMI1 was preferentially expressed in cones at heterochromatic foci. BMI1 inactivation in human embryonic stem cells was compatible with retinal induction but impaired cone terminal differentiation. Despite this developmental arrest, BMI1-deficient cones recapitulated several anomalies observed in Bmi1(-/-) photoreceptors, such as loss of heterochromatin, activation of tandem repeats and induction of p53, revealing partly conserved biological functions between mouse and man.

Alternate JournalDevelopment
PubMed ID26965367