NANOGNB, originally labeled as LOC360030, was not listed in the survey in release 35.1 because of its weak similarity to homeodomain sequences (Holland et al, 2007). In release 37.1 it is annotated as 'homeobox C14' but this name is misleading, as it could cause confusion with Hoxc cluster genes which are not at all closely related. LOC360030 locates to chromosome 12 (12p13.31), only about 15 kb from NANOG. However, its homeodomain sequence is very different with the one in NANOG and also other homeobox genes. The detected homeodomain sequence, though very divergent, contains conserved motifs of homeodomain and secondary structure prediction suggests it can fold into three alpha helices, compatible with a homeodomain-like three-dimension structure. However, since its homeodomain sequence is highly divergent from those encoded by other homeobox genes, it is difficult to consider it as a member of one of the 11 established homeobox gene classes. It could be a tandem duplicate of NANOG, but if so it has undergone massive sequence divergence. Three other sequences with high similarity can be found on human chromosomes 2, 12 and X, and are considered as pseudogenes of NANOGNB. Orthologous genes can be found in other primates, horse and dog, though the locus has been lost in rodents (Zhong and Holland 2011).|
Zhong YF, Holland PWH (2011) BMC Evol Biol 11: 169-204.