MicroRNAs(miRNAs)areaclassofshort,endogenously-initiatednon-codingRNAsthatpost-transcriptionallycontrolgeneexpressionviaeithertranslationalrepressionormRNAdegradation.ItisbecomingevidentthatmiRNAsareplayingsignificantrolesinregulatorymechanismsoperatinginvariousorganisms,includingdevelopmentaltimingandhost-pathogeninteractionsaswellascelldifferentiation,proliferation,apoptosisandtumorigenesis.Likewise,asaregulatoryelement,miRNAitselfiscoordinativelymodulatedbymultifariouseffectorswhencarryingoutbasicfunctions,suchasSNP,miRNAediting,methylationandcircadianclock.Thismini-reviewsummarizedthecurrentunderstandingofinteractionsbetweenmiRNAsandtheirtargets,includingrecentadvancementsindecipheringtheregulatorymechanismsthatcontrolthebiogenesisandfunctionalityofmiRNAsinvariouscellularprocesses.