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Published February 1992 | public
Journal Article

Modulation of sea urchin actin mRNA prevalence during embryogenesis: Nuclear synthesis and decay rate measurements of transcripts from five different genes

Abstract

The parameters determining the prevalence of the five actin gene transcripts that are differentially expressed during embryogenesis in the sea urchin Strongylocentrotus purpuratus were measured in vivo. These results and previous studies show that the developmental appearance of the cytoskeletal actin mRNA, CyI, CyIIa, CyIIb, and CyIIIa, and the muscle-specific actin message M, is transcriptionally regulated. The cytoskeletal actin genes are activated at the 64-cell stage or shortly thereafter. At this stage the specification of the early embryonic lineages has just completed. M gene transcription was detected only after muscle cells appear in the late embryo. The CyI, CyIIa, and CyIIb genes are transcribed at a moderate rate that does not vary significantly during development. In contrast, during late cleavage CyIIIa transcripts are produced at the maximum rate observed for structural genes in this embryo. In later stages, CyIIIa transcription is reduced at least 30-fold. The rate at which new actin transcripts enter the cytoplasm was also measured. The data show that essentially all primary actin gene transcripts are processed into mature messages. Actin message stability does not change during development. The mRNA half-life of the various messages was found to range from 4 hr to greater than 14 hr.

Additional Information

© 1992 Academic Press, Inc. Accepted October 30, 1991. We thank R. A. Cameron and B. R. Hough-Evans for critically reviewing this manuscript. We would like to thank Patrick Leahy for help in the collection of gametes and culturing of embryos. This research was supported by NIH grant HD-05753.

Additional details

Created:
August 20, 2023
Modified:
October 25, 2023