Expression patterns of genes encoding small GTPases Ras-dva-1 and Ras-dva-2 in the Xenopus laevis tadpoles.

Small GTPases of the recently discovered Ras-dva family are specific to the Vertebrate phylum. In Xenopus laevis, Ras-dva-1 is expressed during gastrulation and neurulation in the anterior ectoderm where it regulates the early development of the forebrain and cranial placodes (Tereshina et al., 2006). In the present work, we studied the expression of Ras-dva-1 at later developmental stages. As a result, the Ras-dva-1 expression was revealed in the eye retina, epiphysis (pineal gland), hypophysis (pituitary), branchial arches, pharynx, oesophagus, stomach and gall bladder of swimming tadpoles. Additionally, we investigated for the first time the expression pattern of Ras-dva-2. This gene encodes a protein belonging to a novel sub-group of Ras-dva GTPases that we identified by phylogenetic analysis within Ras-dva family. In contrast to Ras-dva-1, Ras-dva-2 is not expressed before the swimming tadpole stage. At the swimming tadpole stage, however, Ras-dva-2 transcripts can be detected in the eye retina and brain. Later in development, the expression of Ras-dva-2 can also be revealed in the mesonephros and stomach.