H2A histone family, member X; Variant histone H2A which replaces conventional H2A in a subset of nucleosomes. Nucleosomes wrap and compact DNA into chromatin, limiting DNA accessibility to the cellular machineries which require DNA as a template. Histones thereby play a central role in transcription regulation, DNA repair, DNA replication and chromosomal stability. DNA accessibility is regulated via a complex set of post-translational modifications of histones, also called histone code, and nucleosome remodeling. Required for checkpoint-mediated arrest of cell cycle progression in resp [...] (143 aa)

serum response factor (c-fos serum response element-binding transcription factor); SRF is a transcription factor that binds to the serum response element (SRE), a short sequence of dyad symmetry located 300 bp to the 5’ of the site of transcription initiation of some genes (such as FOS). Required for cardiac differentiation and maturation (508 aa)

cyclin-dependent kinase inhibitor 1C (p57, Kip2); Potent tight-binding inhibitor of several G1 cyclin/CDK complexes (cyclin E-CDK2, cyclin D2-CDK4, and cyclin A-CDK2) and, to lesser extent, of the mitotic cyclin B-CDC2. Negative regulator of cell proliferation. May play a role in maintenance of the non- proliferative state throughout life (316 aa)

cyclin-dependent kinase inhibitor 1B (p27, Kip1); Important regulator of cell cycle progression. Involved in G1 arrest. Potent inhibitor of cyclin E- and cyclin A-CDK2 complexes. Forms a complex with cyclin type D-CDK4 complexes and is involved in the assembly, stability, and modulation of CCND1- CDK4 complex activation. Acts either as an inhibitor or an activator of cyclin type D-CDK4 complexes depending on its phosphorylation state and/or stoichometry (198 aa)

cone-rod homeobox; Binds and transactivates the sequence 5’-TAATC[CA]-3’ which is found upstream of several photoreceptor-specific genes, including the opsin genes. Acts synergistically with other transcription factors, e.g. NRL and RX, to regulate photoreceptor cell-specific gene transcription. Essential for the maintenance of mammalian photoreceptors (299 aa)

delta-like 1 (Drosophila); Acts as a ligand for Notch receptors. Blocks the differentiation of progenitor cells into the B-cell lineage while promoting the emergence of a population of cells with the characteristics of a T-cell/NK-cell precursor (723 aa)

FLT3-interacting zinc finger 1; May be a transcriptional repressor of NRL function in photoreceptors. Does not repress CRX-mediated transactivation (By similarity) (496 aa)

PITPNM family member 3; Catalyzes the transfer of phosphatidylinositol and phosphatidylcholine between membranes (in vitro) (By similarity). Binds calcium ions (974 aa)