Expression of VEGF splice variants 144/145 and 205/206 in adult male tissues.

Currently, at least five different mRNA species encoding vascular endothelial growth factor-A (VEGF-A) have been characterized. These variants result from alternative splicing of the VEGF-A transcript and encode human isoforms of VEGF protein of 121, 145, 165, 189, and 206 amino acids. In the rat, a similar profile of VEGF-A splice variants has been described, each encoding one fewer amino acid than the human species. Studies of mammalian tissues have shown that these mRNA isoforms vary in abundance. Whereas VEGF 188/189, 164/165, and 120/121 (rat/human, respectively) are the predominant forms expressed in most tissues and cells examined, VEGF 144/145 and 205/206 are rare variants. Previously, VEGF 144/145 had been detected only in placental and uterine tissues and endometrial carcinoma cell lines, whereas VEGF 205/206 was detected only in fetal liver and placenta. Using an RT-PCR technique, cDNA cloning, and sequencing, we have detected and confirmed the presence of mRNA encoding VEGF 144/145 and 205/206 in both adult rat lung and penis. Therefore, these low-abundance VEGF splice variants have a more diverse expression pattern than originally predicted.