title: A retinoblastoma orthologue is a major regulator of S-phase, mitotic, and developmental gene expression in Dictyostelium.
abstract: BACKGROUND
  The retinoblastoma tumour suppressor, Rb, has two major functions. First, it represses genes whose products are required for S-phase entry and progression thus stabilizing cells in G1. Second, Rb interacts with factors that induce cell-cycle exit and terminal differentiation. Dictyostelium lacks a G1 phase in its cell cycle but it has a retinoblastoma orthologue, rblA.
  
  
  RESULTS
  Using microarray analysis and mRNA-Seq transcriptional profiling, we show that RblA strongly represses genes whose products are involved in S phase and mitosis. Both S-phase and mitotic genes are upregulated at a single point in late G2 and again in mid-development, near the time when cell cycling is reactivated. RblA also activates a set of genes unique to slime moulds that function in terminal differentiation.
  
  
  CONCLUSIONS
  Like its mammalian counterpart Dictyostelium, RblA plays a dual role, regulating cell-cycle progression and transcriptional events leading to terminal differentiation. In the absence of a G1 phase, however, RblA functions in late G2 controlling the expression of both S-phase and mitotic genes.
authors: Biology Department and Centre for Structural and Functional Genomics, Concordia University, Montreal, Canada.
authors: Kimchi
authors: K
authors: Strasser
authors: Gareth
authors: G
authors: Bloomfield
authors: Asa
authors: A
authors: MacWilliams
authors: Adriano
authors: A
authors: Ceccarelli
authors: Harry
authors: H
authors: MacWilliams
authors: Adrian
authors: A
authors: Tsang
mesh_terms: D003080:Cold Temperature; D004023:Dictyostelium / Q000166:cytology* / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D053263:Gene Regulatory Networks / Q000235:genetics; D050437:Genes, Developmental / Q000235:genetics; D017125:Genes, Protozoan / Q000235:genetics; D008938:Mitosis / Q000235:genetics*; D008957:Models, Genetic; D020411:Oligonucleotide Array Sequence Analysis; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D016160:Retinoblastoma Protein / Q000737:chemistry*; D016196:S Phase / Q000235:genetics*; D017386:Sequence Homology, Amino Acid
chemical_list: D015800:Protozoan Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; D016160:Retinoblastoma Protein