Mab21 gene family has its first member identified in C. elegans. Over the years, additional family members were defined in many different species from invertebrates to verterbrates. Across these species, Mab21 sequence is highly conserved although no known functional domain has been defined up to date. In C. elegans, mab-21 plays an important role in ray patterning and sensory organ formation. In all vertebrate systems examined, there are two Mab21 homologs, Mab21l1 and Mab21l2. Mab21l1 and Mab21l2 have overlapping expression window. Mab21l2 has a higher expression level in mid and hind-brain during embryonic development. Anti-sense oligo treatment of mouse embryo blocking the expression of Mab21l2 caused the abnormal formation of neural structure. In addition, homozygous Mab21l2 mutant...[ Read more ]

Mab21 gene family has its first member identified in C. elegans. Over the years, additional family members were defined in many different species from invertebrates to verterbrates. Across these species, Mab21 sequence is highly conserved although no known functional domain has been defined up to date. In C. elegans, mab-21 plays an important role in ray patterning and sensory organ formation. In all vertebrate systems examined, there are two Mab21 homologs, Mab21l1 and Mab21l2. Mab21l1 and Mab21l2 have overlapping expression window. Mab21l2 has a higher expression level in mid and hind-brain during embryonic development. Anti-sense oligo treatment of mouse embryo blocking the expression of Mab21l2 caused the abnormal formation of neural structure. In addition, homozygous Mab21l2 mutants have eye defective phenotype. By RT-PCR detection, Mab21l2 expression level was higher in eye, cerebellum, mid-brain, medulla and spinal cord than the other tissues at the adult stage. These observations suggest that Mab21l2 is playing a role in neural development. To study the role of Mab21l2 in a simple neural differentiation paradigm, Mab21l2 expression level in different cell types was examined. Its developmental regulation during neural differentiation and the presence of neural specific regulatory element were monitored. By RT-PCR detection and northern analysis, Mab21l2 mRNA was enriched in neurons but not in myoblast and fibroblast. Its expression level was up-regulated in the process of neural differentiation. Promoter deletion and reporter assay also revealed the presence of neural specific positive regulatory element and the neural induction responsive element of Mab21l2. Furthermore, yeast-two-hybrid screen was attempted to identify interacting partners of MAB21L2 presence in neural tissue. MAB21L2 was found to interact with the SIN3A and SIN3B.