Abstract
Two distinct c-Myc RNA classes have been identified in Xenopus laevis, presumably expressed from the duplicated c-Myc locus (1, 6). The major Xenopus c-Myc transcripts arise from sites termed P1 and P2 similarly to those of the mammalian c-Myc genes. I have used a cloned Xenopus c-Myc gene to examine the regulated pattern of expression from this gene during early Xenopus embryogenesis. Analysis of the pattern of transcript processing indicates that not only are P1 and P2 differentially active during early development but alternatively spliced c-Myc RNAs are generated which contain sequences of the first intron. These intron-1 containing c-Myc RNAs are generated by alternative splicing of transcripts initiated from the major transcription start site, P2, and are observed only in RNA samples from post-midblastula embryos or Xenopus tissue culture cells. Xenopus tissue culture cells synthesize two major c-Myc proteins (p61 and p64). Xenopus RNAs that do not contain intron-1 sequences synthesize only the p61 species. Two closely spaced ATG codons at the 5' end of exon-2 are utilized equivalently to generate a p61 doublet. Intron-1 containing RNAs utilize an ATG codon in the intron sequences to synthesize the p64 species as well as the exon-2 ATG codons to synthesize the p61 doublet.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.