Expression of thymosin beta4 during chick development

Abstract

We cloned the chick homologue of Homo sapiens thymosin beta4, encoding a G-actin sequestering factor which plays an important role in angiogenesis, cell motility and tumorigenesis. The thymosin beta4 gene is highly conserved between chick and human. Its expression was analyzed during different stages of development. At early stages thymosin beta4 is expressed in the mesoderm and endoderm and in Hensen's node. Later, thymosin beta4 transcripts are found in the head mesenchyme, somites, dorsal root ganglia, neural tube, brain, blood vessels and feather buds. The pattern of thymosin beta4 expression in blood vessels indicates a function mainly in development of the blood circulatory system which closely parallels findings in vitro. The observed expression pattern shows a high similarity to expression data published for mice, mainly in the heart and in the nervous system. Important new aspects are the early onset of expression, the expression in the mesoderm preceding heart formation and the involvement in feather development.

Thymosin β4 and angiogenesis: modes of action and therapeutic potential

“…Based on its prominent expression pattern in blood vessels, Tb4 similarly appears to play a role in the developing cardiovascular system of the chick [57]. Interestingly, the earliest expression of Tb4 was detected in the extra-embryonic blood-circulatory system, a lineage which has not yet been investigated, in other species.…”

Occurrence of thymosin β4 in human breast cancer cells and in other cell types of the tumor microenvironment

“…In contrast, however, Yamamoto et al [21] described down-regulation of thymosin b4 in metastatic cells of colorectal carcinomas. The role of thymosin b4 in angiogenesis is supported by experimental data [6,7] as well as by studies localizing the polypeptide to the endothelium of developing blood vessels and to the heart [14,22,23]. At later stages of development, not all endothelial cells were positive for thymosin b4, suggesting that the peptide may play a role in the developing endothelium rather than in sustaining the mature vessel [22].…”

Possible functional involvement of thymosin beta 4 in developing tooth germ of mouse lower first molar

“…The expression of Tb4 has also been studied in chick embryogenesis, especially regarding the development of the nervous system, cardio vascular system and feather buds (Dathe and Brand-Saberi 2004). The expression of Tb4 has been detected in the mouse embryonic nervous system and during the differentiation of embryonic cells into cardiac cells, and the developing rat brain, thus indicating that the expression of Tb4 is involved in the development of the heart and nervous system, (Go´mez-Ma´rquez et al 1993;Gó mez-Ma´rquez et al 1996;Anado´n et al 2001).…”