[The human son gene: the large and small transcripts contains various 5'-terminal sequences]

Human son gene was previously identified by cloning and hybridization to GC-rich rat genomic fragment. After several cycles of human placenta library walking we were able to identify and clone two alternative transcripts of this gene. Recently we have determined nucleotide sequence of small son gene transcript, coding region of which contains four areas of complete tandem repeats. Here we report the structure of the part (2.9 kb) of large transcript of son gene from close to its 5'-end to the end of sequence, unique for this transcript. Comparison of nucleotide sequences of two transcripts indicates that they have common 3'-ends and, probably, arise from alternative splicing. 5' proximal part of large transcript contains two areas of complete tandem repeats not present in small transcript. Results of analysis of this area support our model for forming son gene tandem repeats structure by duplication, mutation and natural selection at the protein level.