HeLa cell messenger RNAs of widely differing sizes encode certain heat shock proteins in theMrregion of 72 000-74 000

Abstract
Cloned cDNA sequences coding for specific 72 000–74 000 M r HeLa cell heat shock proteins (HSPs) have been used as probes to examine cytoplasmic and nuclear RNA of heat shocked HeLa cells. The mRNAs for these HSPs vary widely in size. Whilst the β‐, δ‐ and ε‐HSPs are encoded in mRNAs of 1.9 kb, the γ‐HSP arises from an mRNA three times that size. A search for putative nuclear precursors to these mRNAs revealed high M r candidates at 15.8 kb which accumulate 1–2 h after the initial heat shock, thus supporting the notion that transcriptional control is important in the initial heat shock response.