Structure and expression of the chicken retinoblastoma gene

• Published in: Cell growth & differentiation Vol. 5; no. 2; pp. 221 - 230
• Main Authors: BOEHMELT, G, ULRICH, E, KURZBAUER, R, MELLITZER, G, BIRD, A, ZENKE, M
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA American Association for Cancer Research 01.02.1994
• Subjects: Amino Acid Sequence; Animals; Base Sequence; Biological and medical sciences; Blotting, Southern; Blotting, Western; Chick Embryo; Chickens - genetics; DNA - genetics; DNA - metabolism; DNA, Complementary - analysis; DNA, Complementary - metabolism; Fundamental and applied biological sciences. Psychology; Gene Expression; Genes, Retinoblastoma; Genes. Genome; Humans; Introns; Mice; Molecular and cellular biology; Molecular genetics; Molecular Sequence Data; Recombinant Proteins - biosynthesis; Recombinant Proteins - chemistry; Retinoblastoma Protein - biosynthesis; Retinoblastoma Protein - chemistry; Retinoblastoma Protein - genetics; Sequence Homology, Amino Acid; Transcription, Genetic; Xenopus; Vertebrata; Transcription; Gene product; Chicken; Aves; Retinoblastoma; Gene expression
• ISSN: 1044-9523; 2377-0732

The molecular cloning and initial characterization of the complementary DNA encoding the chicken homologue of the human retinoblastoma susceptibility gene product Rb are described. Chicken Rb (chRb) was found to be highly homologous to human, mouse, and Xenopus Rb in primary amino acid sequence, underlining its conserved function in cell cycle control in higher eukaryotes. The highest level of homology was found within the Rb "pocket domains" and at the Rb COOH terminus, whereas the extreme NH2 terminus of chRb is divergent. We also show that transcription of chRb initiates at multiple start sites within a DNA segment which represents a CpG island. ChRb is transcribed as a 4.7-kilobase (kb) mRNA species in a variety of normal chicken tissues and oncogene-transformed hematopoietic cells. However, in v-rel-transformed cell lines, a variant 3.1-kb Rb-specific mRNA was detected in addition to the 4.7-kb transcript. ChRb is expressed as a 104 kilodalton protein and is therefore slightly smaller than the mammalian Rb proteins.