The interplay of messenger RNA (mRNA), protein, produced via translation of this RNA, and nonprotein coding RNA (ncRNA) may include regulation of the ncRNA production by protein and (i) ncRNA-mRNA association or (ii) ncRNA-protein association resulting in degradation of the corresponding complex. The kinetic models, describing these two scenarios and taking into account that the association of ncRNA with a target occurs after ncRNA conversion from the initial form to the final form (e. g., from a long RNA to microRNA), are found to predict oscillations provided that the rate of ncRNA formation increases with increasing protein population. (c) 2008 Elsevier B.V. All rights reserved.