Nickel and cobalt resistance proteins CnrA, CnrB, CnrC CnrH and CnrR may be involved in the regulation of CNR. CnrH alone is able to activate cnr expression, and both CnrY and CrnX are needed for nickel induction of CnrH (PubMed:10671463). In the absence of wild-type CnrY (due either to a frameshift, PubMed:10671463 or absence of the transcript, PubMed:10671464), nickel and cobalt resistance is constitutive, indicating that CrnY may act as a repressor (PubMed:10671463) or an anti-sigma factor (PubMed:10671464). By nickel and cobalt. To A.xylosoxydans NccY.