[Alternative splicing of the FMR1 gene in human fetal tissues].

OBJECTIVE

To gain more insight into biological role of the alternative splicing of the FMR1 gene, isoforms of the FMR1 mRNA from human fetal heart, spleen, liver and kidney were analyzed.

METHODS

RNAs were isolated from the tissues of an abortion fetus (approximately 6 months postconception). Alternative splicing patterns of the FMR1 mRNA were analyzed by RT-PCR and cloning strategy.

RESULTS

One isoform of the FMR1 mRNA was found to be dominant in all of the four tissues. The major isoform was as same as the dominant one in the fetal cortex but was different from the major isoform in adult brain. The difference between the major isoforms in the fetal tissues and adult brain was the splicing out or retaining the peptide encoded by exon 12 and exon 17.

CONCLUSION

This result suggested a developmental switch of alternative splicing of the FMR1 gene. The difference between the major isoforms in the fetal tissues and adult brain suggested the two peptides may have special roles in related developmental stages.