Suzuki K, Yamamoto T, Inoue J
Department of Oncology, University of Tokyo, Japan.
Nucleic Acids Res. 1995 Nov 25;23(22):4664-9. doi: 10.1093/nar/23.22.4664.
We have molecularly cloned cDNA encoding a new Rel-related protein in Xenopus laevis. Nucleotide sequencing revealed that the product is most homologous to mammalian RelB in its N-terminal region. Furthermore, the putative protein kinase A phosphorylation site (RRPS), found in most of the Rel family proteins, but replaced by QRLT in mammalian RelB, is replaced by QRIT, indicating that our cDNA most likely encodes the Xenopus homolog of mammalian RelB (XrelB). As in the case of mouse RelB, XrelB alone does not bind to DNA efficiently, while XrelB/human p50 heterodimers bind to kappa B sites and activate transcription. XrelB transcripts are present at all stages of oocyte maturation and in adult tissues examined. However, in staged embryos XrelB is undetectable from neurula to stage 28 and resumes expression at stage 47, while Xrel1/XrelA, the Xenopus homolog of p65, has been demonstrated to be expressed throughout embryogenesis. These results raise the possibility that XrelB and Xrel1/XrelA play different roles in the development of X.laevis.
我们已从非洲爪蟾中分子克隆出编码一种新的Rel相关蛋白的cDNA。核苷酸测序显示，该产物在其N端区域与哺乳动物RelB最为同源。此外，大多数Rel家族蛋白中存在的假定蛋白激酶A磷酸化位点（RRPS），在哺乳动物RelB中被QRLT取代，在我们克隆的cDNA中则被QRIT取代，这表明我们的cDNA最有可能编码哺乳动物RelB的非洲爪蟾同源物（XrelB）。与小鼠RelB的情况一样，单独的XrelB不能有效地结合DNA，而XrelB/人p50异二聚体则能结合κB位点并激活转录。XrelB转录本存在于卵母细胞成熟的各个阶段以及所检测的成年组织中。然而，在分期胚胎中，从神经胚期到28期均未检测到XrelB，而在47期恢复表达，而p65的非洲爪蟾同源物Xrel1/XrelA已被证明在整个胚胎发育过程中均有表达。这些结果增加了XrelB和Xrel1/XrelA在非洲爪蟾发育中发挥不同作用的可能性。
