Analysis of foetal expression sites of human type II DNA topoisomerase α and β mRNAs by in situ hybridisation

摘要

We present the first unalysis of live sites of expression of DNA topoisomerase II a and II y3 mRNAs in human foetal tissues by in situ hybridisation, using S-radiolabelled probes. This revealed differential Idealisation of topoisomerase II a and II/3 mRNAs in a range of foetal organs, including foetul kidney (developing slruelures within the neogenic zone), brain (cortical layers), small intestine (crypt epithelium and muscle), liver (hepatoeyles), lung (smooth muscle, and epithelium in the lining of primitive lung buds) and placenta (troplioblaslic epithelium). The intensity of expression of topoisomerase lla mRNA appeared higher than that of topoisomerase II/3, although topoisomerase 11) mRNA was expressed in a broader range of cell types. The distinct patterns of expression of topoisomerase IIa and /a mRNAs indicate differential regulation of these genes, suggesting that the two isoforms may play important but different roles in foetal development, with topoisomerase II a being expressed most strongly in zones of proliferation.