Some somatic sequences are absent or exceedingly rare in Xenopus oocyte RNA

Abstract

A variety of Xenopus laevis cDNA clones derived from somatic cell RNAs were hybridized to oocyte pA+ RNA separated on Northern gels. We were unable to detect oocyte pA+ sequences complementary to three undefined tadpole cDNA clones. With one of these clones, a complex pattern of bands appears during embryogenesis. With the other two clones, a single band appears. Two additional tadpole clones hybridize to both oocyte and tadpole RNA, but yield a more complex RNA pattern from embryos than from oocytes. One of these additional tadpole clones has complementarity to actin DNA, suggesting that the additional RNA band which appears during embryogenesis is α-actin mRNA (E. A. Sturgess, J. E. M. Ballantine, H. R. Woodland, P. R. Mohun, C. D. Lane, and G. J. Dimitriadis, 1980, J. Embryol. Exp. Morphol. 58, 303-320). We have also failed to detect hybridization to oocyte pA+ RNA with one vitellogenin and three adult globin cDNA clones. Reconstruction experiments with purified globin mRNA from anemic adult blood cells set the lower level of sensitivity for globin mRNA at one part in 106. The data suggest that some Xenopus mRNA sequences are absent or very rare in the oocyte pA+ RNA population. © 1982.