A serum response factor homologue is expressed in ectodermal tissues during development of the crustacean Artemia franciscana

Complementary DNA clones have been isolated from the crustacean Artemia fra nciscana coding for a serum response factor (SRF)-homologue that is more th an 96% identical to human and Drosophila melanogaster SRFs in their MADS bo xes. The SRF homologue is expressed in ectodermal tissues, as determined by in situ hybridization experiments. A SRF-binding site has been identified in the promoter region of the Actin403 gene that is also expressed in ectod ermal tissues, in accordance with its transcriptional regulation by the SRF homologue. The mRNA coding for A. franciscana SRF is present at similar le vels in cryptobiotic encysted embryos and in developing nauplii. However, t here is a significant increase in CArG-binding activity at the later develo pmental stage, indicating a postranscriptional regulation of SRF during A. franciscana embryonic development. (C) 2000 Elsevier Science Ireland Ltd. A ll rights reserved.