Molecular cloning of multiple isoforms of synaptojanin 2 and assignment of the gene to mouse chromosome 17A2-3.1.

Synaptojanin 2 is an inositol polyphosphate 5'-phosphatase that appears to be regulated by alternative splicing. By screening mouse cDNA libraries derived from either mouse day 16 embryo or adult liver, we have identified additional synaptojanin 2 cDNAs that represent six new isoforms of the protein. This finding, together with other reports, indicates the presence of eight isoforms of synaptojanin 2. Sequence analysis of our cDNA clones suggests that there are at least two putative initiation sites and at least six different sequences coding for the carboxyl-terminus of the molecule. In addition, we have mapped synaptojanin 2 to mouse chromosome 17 band A2-3.1 by fluorescence in situ hybridization.