STRUCTURE OF ALDOLASE-A (MUSCLE-TYPE) CDNA AND ITS REGULATED EXPRESSION IN OOCYTES, EMBRYOS AND ADULT TISSUES OF XENOPUS-LAEVIS

We obtained cDNA (XALDA; 1466 bp) for Xenopus laevis aldolase A gene ( muscle-type), whose amino acid sequence had 88% similarity to those of mammalian aldolase A genes. XALDA mRNA occurred abundantly in skeleta l muscle and at low levels also in other adult tissues, and such mRNA distribution was reflected in zymograms. In oocytes XALDA mRNA occurre d at a relatively high level from stage I, and the mRNA level peaked a t stage II, then decreased in later stages. XALDA mRNA in the full-gro wn oocyte was inherited as maternal mRNA throughout maturation and fer tilization until midblastula stage, but its level became very low duri ng gastrula and early neurula stages, and then increased greatly in la ter stages, While maternal XALDA mRNA was distributed uniformly in ear ly embryos, mRNA zygotically expressed after late neurula stage occurr ed mainly in somites. In blastula animal caps XALDA mRNA occurred at a low level, but the expression was greatly enhanced by activin treatme nt. Thus, in Xenopus laevis aldolase A gene is actively transcribed in earlier phase of oogenesis, inherited as maternal mRNA in early embry os in a cell-type nonspecific way, then in later phases of embryogenes is, it is strongly expressed in somites with its concomitant ubiquitou s expression at low levels in almost all the other cell types. (C) 199 7 Elsevier Science B.V.