A fluorescence in situ hybridisation study of the regulation of histone mRNA levels during the cell cycle of Trypanosoma brucei.

We have analysed the regulation of histone H2A, H2B, H4 and beta-tubulin RNA levels during the cell cycle of asynchronous cultures of Trypanosoma brucei by fluorescence in situ hybridisation. Whereas tubulin mRNA is detectable at high levels during the entire cell cycle, histone mRNA presence peaks during S phase and is not detectable during all other stages of the cell cycle within the sensitivity limits of this technique. We show that fluorescence in situ hybridisation can be used to characterise the distribution patterns of cell cycle regulated transcripts in asynchronous cell culture systems and discuss the possibilities and limitations of quantification of hybridisation patterns by means of computer-assisted image analysis.