A PROLACTIN-INDUCIBLE T-CELL GENE-PRODUCT IS STRUCTURALLY SIMILAR TO THE ASPERGILLUS-NIDULANS NUCLEAR-MOVEMENT PROTEIN NUDC

Clone 15 (c15) was originally identified as a PRL-inducible gene in ac tivated T cells, Sequence analysis of c15 revealed that the last 94 am ino acids of c15 are 68% identical and 78% similar to the filamentous fungus Aspergillus nidulans nuclear movement protein NUDC. The identif ication of the mammalian (rat) c15 protein suggests that the carboxy-t erminal NUDC-like region has been conserved over evolution for an impo rtant structure and/or function. To determine whether c15 is functiona lly analogous to NUDC, complementation studies were performed using th e inducible/repressible pAL5 vector system. The results of the complem entation experiments show that the full-length mammalian c15 protein i s not only capable of rescuing the nuclear movement defect of the nudC 3 mutants, but is also able to restore the expression of the downstrea m endogenous NUDF protein to near wild type levels. These results indi cate that rat c15 and fungal NUDC not only share similar structures, b ut also serve similar functions, Taken together, the structural and fu nctional conservation between c15 and NUDC is consistent with the noti on that c15 is the rat homolog of nudC and has therefore been given th e name RnudC.