Assignment of the human reticulon 4 gene (RTN4) to chromosome 2p14-->2p13 by radiation hybrid mapping.

The human reticulon I gene (RTN1) cloned from a smallcell lung cancer (SCLC) NC1-H82 cell line (Roebroek et al., 1993) and mapped to chromosome 14q21→q22 (Kools et al., 1994) has three alternative transcripts (3.4, 2.3, and 1.8 kb) which can produce three different proteins (NSP-A with 776 amino acids, NSP-B with 356 amino acids and NSP-C with 208 amino acids.) with common carboxyl-terminal regions. These proteins are anchored to membranes of the endoplasmic reticulum and are collectively designated reticulons (Senden et al., 1994). The NSP-A and NSP-C proteins are expressed only in SCLC cells with neuroendocrine phenotypes as shown by Northern blot analysis, so it was proposed that the NSP proteins exist in some relationship with the occurrence of neuroendocrine SCLC (van de Velde et al., 1994). Two other genes whose 3)-regions are homologous to that of RTN1 were cloned and mapped to chromosome 19q13.3 and 11q13 respectively (Roebroek et al., 1998; Moreira et al., 1999). Although their functions are still not clear, they are regarded as members of the reticulon gene family and are called RTN2 and RTN3. Recently, a novel gene whose 3)-region is also homologous to that of RTN1 and which also has 3 alternative transcripts (4632, 2235 and 1617 bp, GenBank nos. AF148537, AF148538 and AF087901) was cloned in our laboratory and named RTN4 (including RTN4A, RTN4B and RTN4C) by the HUGO Nomenclature committee. Here, we report that the RTN4 gene was mapped to chromosome 2p14→p13 by using a radiation hybrid mapping panel.