Abstract: Objective To characterize a new alternative splicing isoform of human vascular endothelial growth factor (VEGF)
gene. Methods The total RNA was extracted from the lung tissue of a legally aborted 4-month-old fetus and amplified by
RT-PCR. The amplified product was cloned into the plasmid pMD18-T and plasmid pcDNA3.1- for sequence analysis. Results
Electrophoresis of the RT-PCR products displayed one short band for VEGF121 (487 bp) and a long band. The latter was
characterized to contain two fragments: one was normal VEGF165 (619 bp), and the other (639 bp) had an identical nucleotide
sequence to VEGF165 with a 20 bp fragment inserted between exons 3 and 4. Sequence analysis showed that this 20-bp
nucleotide was inserted from the 3’ end of the third intron containing a splicing signal, thus causing shift mutation in the
reading frame of VEGF gene and early appearance of the stop codon UAG in the middle of exon 4. Conclusion A new
alternative splicing isoform of VEGF probably exists in the lung tissue of a legally aborted human fetus, and its biological
significance remains to be further investigated.