PILC OF NEISSERIA-MENINGITIDIS IS INVOLVED IN CLASS-II PILUS FORMATION AND RESTORES PILUS ASSEMBLY, NATURAL TRANSFORMATION COMPETENCE AND ADHERENCE TO EPITHELIAL-CELLS IN PILC-DEFICIENT GONOCOCCI

Type 4 piIi produced by the pathogenic Neisseria species constitute pr imary determinants for the adherence to host tissues, In addition to t he major pilin subunit (PIIE), neisserial piIi contain the variable Pi IC proteins represented by two variant gene copies in most pathogenic Neisseria isolates, Based upon structural differences in the conserved regions of PIIE, two pilus classes can be distinguished in Neisseria meningitidis, For class I pill found in both Neisseria gonorrhoeae and N, meningitidis, PiIC proteins have been implicated in pilus assembly , natural transformation competence and adherence to epithelial cells, In this study, we used primers specific for the piIC2 gene of N, gono rrhoeae strain MS11 to amplify, by the polymerase chain reaction, and clone a homologous piIC gene from N. meningitidis strain A1493 which p roduces class II pill, This gene was sequenced and the deduced amino a cid sequence showed 75.4% and 73.8% identity with the gonococcal PiIC1 and PiIC2, respectively, These values match the identity value of 74. 1% calculated for the two N. gonorrhoeae MS11 PiIC proteins, indicatin g a horizontal relationship between the N, gonorrhoeae and N, meningit idis piIC genes, We provide evidence that PiIC functions in meningococ cal class II pilus assembly and adherence, Furthermore, expression of the cloned N. meningitidis piIC gene in a gonococcal piIC1,2 mutant re stores pilus assembly, adherence to ME-180 epithelial cells, and trans formation competence to the wild-type level, Thus, PiIC proteins exhib it indistinguishable functions in the context of class I and class II piIi.