We describe the isolation and complete sequence of the Xenopus c-fos proto-oncogene. c-fos expression throughout Xenopus development was analysed using a homologous probe derived from the cloned gene. c-fos RNA is accumulated during oogenesis to reach a plateau of 2 x 10(5) transcripts per stage VI oocyte, suggesting an unusual stability of the c-fos message. The amount of RNA per embryo decrea...

We used a peptide antibody to a conserved sequence in the motor domain of kinesins to screen a Xenopus ovary cDNA expression library. Among the clones isolated were two that encoded a protein we named XCTK2 for Xenopus COOH-terminal kinesin 2. XCTK2 contains an NH2-terminal globular domain, a central alpha-helical stalk, and a COOH-terminal motor domain. XCTK2 is similar to CTKs in other organi...

Transcription of ribosomal genes requires, in addition to RNA polymerase I, the trans-acting factors UBF and Rib1 in Xenopus or SL1 in humans. RNA polymerase I transcription is remarkably species specific. Between closely related species SL1 is the sole determinant of this specificity. Between more distantly related species, however, UBF is also a component of this species specificity. Xenopus ...

The function of alpha-melanocyte-stimulating hormone (alpha-MSH) is not known in mammals. It is well-established in the amphibian Xenopus laevis in which alpha-MSH mediates the process of adaptation to a dark background. The amino acid sequence of this hormone is, however, not known in amphibians. In order to determine the primary structure of the precursor protein for alpha-MSH, which in mamma...

We have isolated Xenopus laevis cDNA and genomic clones encoding the neuropeptide Y (NPY) mRNA and gene using a probe from the human NPY gene. The longest open reading frame in the cDNA encodes a peptide 76% identical to human prepro-NPY and 73% identical to rat prepro-NPY. The putative mature Xenopus NPY (XNPY) peptide is 94% identical to both human and rat peptides. A genomic clone containing...