Novel, Highly Expressed Late Nodulin Cene (LjNODI6) from Lotus japonicus

tein and its corresponding gene were designated Nlj16 and LjNOD16, respectively. LjNOD16 was found to be expressed only in the infected cells of L. japonicus nodules. Related DNA sequences could be identified in the genomes of both Glycine max and Medi- cago safiva. In the latter, a homologous mRNA species was detected in the nodules. Unlike LjNOD16, its alfalfa homologs appear to represent low-abundance mRNA species. However, the proteins corresponding to the LjNOD76 and its alfalfa homolog could be detected at similar levels in nodules but not in roots of both legume species. lhe predicted amino acid sequence analysis of nodulin Nlj16 revealed the presence of a long a-helical region and a posi- tively charged C terminus. The former domain has a very high propensity to form a coiled-coil type structure, indicating that nodulin Nlj16 may interact with an as-yet-unidentified protein tar- get(s) in the nodule-infected cells. Homology searches revealed no significant similarities to any known sequences in the databases, with the exception of two related, anonymous Arabidopsis ex- pressed sequence tags.