Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
???displayArticle.abstract???
Src family tyrosine kinases (SFKs) play important roles in cell morphology, differentiation, motility and proliferation. Elevated expression and/or specific activity of Src kinases are characteristic for several types of human cancer. However, little information is available about the role and spatio-temporal expression of SFKs in early embryonic development. In this study we characterized, in Xenopus laevis, the expression patterns of five SFK genes src, fyn, yes, lyn and laloo as well as of the csk gene, a negative regulator of SFKs, using RT-qPCR and in situ hybridisation. We found that transcripts of all SFKs and csk were already detectable in one-cell embryos and their levels similarly oscillated during subsequent development. First, after stage 8, the levels of SFK and csk mRNAs began to decrease, reached a minimum between stages 10 and 28 and increased again. In the later stages (33-45), the levels of fyn, yes and csk mRNAs returned to approximately maternal ones, whereas the src, laloo and lyn mRNA transcripts exceeded, up to about 3.5-6-fold, their maternal levels. In situ hybridisation analysis located the SFK and csk transcripts in the animal hemisphere of Xenopus embryos. Subsequent gastrula stages showed signals in ectodermal cells, mid-neurula stage embryos at neural folds, and the tailbud stages showed strong signals in the brain and neural tube. RT-qPCR concentration profiling along the animal-vegetal axis proved in blastula and gastrula the preferential localisation of yes, src, lyn and csk transcripts towards the animal pole in a gradient-like manner. In contrast, laloo and fyn displayed a vegetal pole preference.
Fig. 3. The spatial and temporal expression patterns of src, fyn, yes, lyn, laloo and csk mRNAs during Xenopus laevis development. (A) Animal (upper row) and lateral (lower row) view of embryonic stages 1, 2, 3 and 8 (blastula) showing enhanced signals in the animal hemisphere. (B) Animal (upper row) and vegetal (lower row) view of gastrula stages (10, 10.5, 11) showing no signal in endodermal cells. (C) Anterior and dorsal view of mid-neurula (stage 16) embryo. SFKs and csk are expressed at the neural folds from anterior to caudal end, but absent from the dorsal midline. (D,E) Lateral view of tailbud (stage 28, 31) embryos. Expression of SFKs and csk persists in the developing brain, neural tube, eye, branchial arches and otic vesicle. Bottom panels depict the expression pattern of myoD used as a positive control. First two panels show lateral and dorsal view of stage 23 embryos and the other two panels show lateral view of stage 31 embryos with the expression pattern of myoD.
Fig. 4. Detailed expression patterns of Xenopus fyn and yes genes. The fyn gene expression patterns (A,B). Anterior view (A) of Xenopus embryo at neurula stage. The arrow shows the expression of the fyn gene in neural folds. Lateral view (B) of a tailbud (stage 31) embryo. Fyn expression persists in the developing brain, neural tube, eye, branchial arches and otic vesicle. The yes gene expression pattern (C,D). Anterior view (C) of Xenopus embryo at neurula stage. The arrow shows the expression of yes gene in neural folds. Lateral view (D) of embryo at stage 31. The arrows show the major expression of yes gene in the developing brain, neural tube, eye, branchial arches and otic vesicle. hb; hindbrain, mb; midbrain, fb; forebrain, ba; branchial arches, ey; eye, ov; otic vesicle.
csk (c-src tyrosine kinase) gene expression in Xenopus laevis embryos, NF stage 28, as assayed by in situ hybridization, lateral view, anteriorleft, dorsal up.
fyn (FYN proto-oncogene, Src family tyrosine kinase) gene expression in Xenopus laevis embryos, NF stage 28, as assayed by in situ hybridization, lateral view, anteriorleft, dorsal up.
hck (HCK proto-oncogene, Src family tyrosine kinase) gene expression in Xenopus laevis embryos, NF stage 28, as assayed by in situ hybridization, lateral view, anteriorleft, dorsal up.
lyn (LYN proto-oncogene, Src family tyrosine kinase) gene expression in Xenopus laevis embryos, NF stage 28, as assayed by in situ hybridization, lateral view, anteriorleft, dorsal up.
src (SRC proto-oncogene, non-receptor tyrosine kinase) gene expression in Xenopus laevis embryos, NF stage 28, assayed by in situ hybridization, lateral view, anteriorleft, dorsal up.
yes1 (YES proto-oncogene 1, Src family tyrosine kinase) gene expression in Xenopus laevis embryos, NF stage 28, as assayed by in situ hybridization, lateral view, anteriorleft, dorsal up.
