Expression of Tra2beta isoforms is developmentally regulated in a tissue- and temporal-specific pattern.

The contribution of Tra2-regulated alternative splicing to mammalian development is unknown. To address the question, we initiated studies by systemically characterizing the gene expression profile of Tra2beta isoforms in human fetal tissue at two different stages (11 and 16 weeks). Tra2beta has at least five isoforms of transcripts (Tra2beta1 approximately 5). Tra2beta1 encodes full-length Tra2beta proteins, whilst Tra2beta3, 4 and 5 encode the truncated proteins. The results show that Tra2beta1 transcript levels are developmentally regulated in a tissue- and temporal-specific pattern, although expression is ubiquitous. Compared to Tra2beta5, the expression of Tra2beta3 and 4 transcripts is significantly restricted and more vigorously regulated in a tissue- and temporal-specific pattern. Western blot analysis shows that Tra2beta1 proteins are ubiquitously expressed, but at a relatively higher level in neural tissues than non-neural tissues. However, there is no direct correlation between the transcript and protein levels for Tra2beta1, suggesting that multiple mechanisms are involved in the regulation of Tra2beta during development. This study indicates that Tra2beta-regulated splicing may contribute to the regulation of mammalian development in a tissue- and temporal-specific pattern.