Lymphocyte and fibroblast chalones: some chemical properties

Experiments with lymphocyte and fibroblast chalones indicate that they are complexed strongly with RNA in tissue extracts; have a molecular weight of less than 10,000 and more than 1,000 daltons, and probably about 5,000 daltons; are strongly cationically charged; and contain mannose and perhaps other carbohydrates.

Mapping of two isoleucine tRNA isoacceptor genes in bacteriophage T5 DNA

T5 bacteriophage codes for the synthesis of more than 14 different tRNA species, which map in four separate clusters in the C segment of the T5 chromosome. In this study, two tRNAile isoacceptor species have been identified by reverse-phase chromatography and shown to be transcribed from two different tRNA loci along the T5 chromosome. The map positions of the tRNA isoacceptors were aided by the use of several T5 deletion mutants in which the position and size of the deleted DNA segments had been previously determined by heteroduplex mapping. Hybridization analysis suggests the presence of some sequence homology between the two tRNAile species.