Quantitative expression studies of aldolase A, B and C genes in developingembryos and adult tissues of Xenopus laevis

We previously cloned cDNAs for all the members (A, B and C) of Xenopus aldo lase gene family, and using in vitro transcribed RNAs as references, perfor med quantitative studies of the expression of three aldolase mRNAs in embry os and adult tissues. A Xenopus egg contains ca. 60 pg aldolase A mRNA and ca. 45 pg aldolase C mRNA, but contains only ca. 1.5 pg aldolase B mRNA. Th e percent composition of three aldolase mRNAs (A:B:C) changes from 56:1.5:4 2.5 (fertilized egg) to 54:10:36 (gastrula), to 71:14.5:14.5 (neurula) and to 73:20:7 (tadpole) during development. These results are compatible with the previous results of zymogram analysis that aldolases A and C are the ma jor aldolases in early embryos, whose development proceeds depending on yol k as the only energy sourer. Aldolase B mRNA is expressed only late in deve lopment in tissues such as pronephros, liver rudiment and proctodeum which are necessary for the future dietary fructose metabolism, and the expressio n pattern is consistent to that in adult tissues. We also show that three a ldolase genes are localized on different chromosomes as single copy genes. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.