GNAZ IN HUMAN FETAL COCHLEA - EXPRESSION, LOCALIZATION, AND POTENTIALROLE IN INNER-EAR FUNCTION

Dissociation of an activated alpha-subunit from the beta-gamma complex directly regulates secondary messenger proteins. To address the poten tial role of G proteins expressed in human fetal cochlea, degenerate o ligonucleotide primers corresponding to the 3'-end of the conserved re gion of a-subunits were used for polymerase chain reaction amplificati on of reverse-transcribed total human fetal cochlear mRNAs; GNAZ and G NAQ were isolated. These two G proteins are unique among the G-protein family because they lack a typical pertussis modification site. GNAZ is expressed in high levels in neural tissue while GNAQ is ubiquitousl y expressed. We characterized GNAZ expression using Northern blots, ti ssue in-situ hybridization and immunohistochemistry techniques to eluc idate the potential role of this protein in inner ear function. Our da ta suggest that GNAZ may play a role in maintaining the ionic balance of perilymphatic and endolymphatic cochlear fluids.