Genome-wide analysis of dorsal and ventral transcriptomes of the Xenopus laevis gastrula

YI DING; GABRIELE COLOZZA; KELVIN ZHANG; YUKI MORIYAMA; DIEGO PLOPER; ERIC A. SOSA; MARIA D. J. BENITEZ; EDWARD M. DE ROBERTIS

DEVELOPMENTAL BIOLOGY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Lugar: Amsterdam; Año: 2016

0012-1606

RNA sequencing has allowed high-throughput screening of differential gene expression in manytissues and organisms. Xenopus laevis is a classical embryological and cell-free extract model system, but its genomic sequence had been lacking due to difficulties arising from allotetraploidy. There is currently much excitement surrounding the release of the completed X. laevis genome (version 9.1) by the Joint Genome Institute (JGI), which provides a platform for genome-wide studies. Here we present a deep RNA-seq dataset of transcripts expressed in dorsal and ventral lips of the early Xenopus gastrula embryo using the new genomic information, which was further annotated by blast searches against the human proteome. Overall, our findings confirm previous results from differential screenings using other methods that uncovered classical dorsal genes such as Chordin, Noggin and Cerberus, as well as ventral genes such as Sizzled, Ventx, Wnt8 and BAMBI. Complete transcriptome-wide Excel files of mRNAs suitable for data mining are presented, which include many novel dorsal- and ventral-specific genes. RNA-seq was very quantitative and reproducible, and allowed us to define dorsal and ventral signatures useful for gene set expression analyses (GSEA). As an example of a new gene, we present here data on an organizer-specific secreted protein tyrosine kinase known as Pkdcc (protein kinase domain containing, cytoplasmic) or Vlk (vertebrate lonesome kinase). Overexpression experimentsindicate that Pkdcc can act as a negative regulator of Wnt/beta-catenin signaling independently of its kinase activity. We conclude that RNA-Seq in combination with the Xenopus laevis complete genome now available provides a powerful tool for unravelling cell-cell signaling pathways during embryonic induction.