title: The length of the fibroin gene in the Bombyx mori genome.
abstract: Radioactive anti-messenger DNA (3H-cDNA) complementary to silk fibroin mRNA has been synthesized using reverse transcriptase. This 3H-cDNA has been found to be a specific and sensitive probe for the detection of fibroin genes in the genome of Brombyx mori. Actinomycin-CsCl gradients give a large separation of the high GC fibroin genes from the bulk DNA. This density shift of fibroin genes has been measured as a function of DNA molecular weight. The data support a model in which a single high GC fibroin gene of 11.6 times 10-6 daltons is surrounded by at least 6 times 10-7 daltons of low GC DNA (30-39 percent). This finding, along with saturation hybridization studies (Suzuki, Gage, and Brown, 1972), demonstrate that the fibroin gene is present in a single copy per haploid genome.
mesh_terms: D000818:Animals; D012831:Bombyx / Q000378:metabolism*; D002499:Centrifugation, Density Gradient; D004247:DNA / Q000378:metabolism; D003609:Dactinomycin; D005349:Fibroins / Q000096:biosynthesis*; D005796:Genes; D008433:Mathematics; D008970:Molecular Weight; D009693:Nucleic Acid Hybridization; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000378:metabolism; D012194:RNA-Directed DNA Polymerase / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D012333:RNA, Messenger; D003609:Dactinomycin; D004247:DNA; D005349:Fibroins; D012194:RNA-Directed DNA Polymerase