Yang, MeilhengBirnbaum, Mark J.MacKay, Carole A.Mason-Savas, AprilThompson, BenjaminOdgren, Paul R.2022-08-232022-08-232008-05-082011-02-16J Cell Physiol. 2008 May;215(2):497-505. <a href="http://dx.doi.org/10.1002/jcp.21331">Link to article on publisher's site</a>0021-9541 (Linking)10.1002/jcp.2133118064667https://hdl.handle.net/20.500.14038/42876Microarray and real-time RT-PCR were used to examine expression changes in primary bone marrow cells and RAW 264.7 cells in response to RANKL. In silico sequence analysis was performed on a novel gene which we designate OC-STAMP. Specific siRNA and antibodies were used to inhibit OC-STAMP RNA and protein, respectively, and tartrate-resistant acid phosphatase (TRAP)+ multinucleated osteoclasts were counted. Antibodies were used to probe bone tissues and western blots of RAW cell extracts +/- RANKL. cDNA overexpression constructs were transfected into RAW cells and the effect on RANKL-induced differentiation was studied. OC-STAMP was very strongly up-regulated during osteoclast differentiation. Northern blots and sequence analysis revealed two transcripts of 2 and 3.7 kb differing only in 3'UTR length, consistent with predictions from genome sequence. The mRNA encodes a 498 amino acid, multipass transmembrane protein that is highly conserved in mammals. It has little overall homology to other proteins. The carboxy-terminal 193 amino acids, however, are significantly similar to the DC-STAMP family consensus sequence. DC-STAMP is a transmembrane protein required for osteoclast precursor fusion. Knockdown of OC-STAMP mRNA by siRNA and protein inhibition by antibodies significantly suppressed the formation of TRAP+, multinucleated cells in differentiating osteoclast cultures, with many TRAP+ mononuclear cells present. Conversely, overexpression of OC-STAMP increased osteoclastic differentiation of RAW 264.7 cells. We conclude that OC-STAMP is a previously unknown, RANKL-induced, multipass transmembrane protein that promotes the formation of multinucleated osteoclasts.en-USAcid PhosphataseAmino Acid SequenceAnimalsAntibodiesBone Marrow CellsBone and BonesCell DifferentiationCell NucleusCells, CulturedImmunohistochemistryIsoenzymesMembrane ProteinsMiceMice, KnockoutMicroarray AnalysisMolecular Sequence DataOsteoclastsRANK LigandRNA, MessengerRNA, Small InterferingRatsReverse Transcriptase Polymerase Chain ReactionSequence AnalysisTransfectionUp-RegulationCell BiologyJournal Articlehttps://escholarship.umassmed.edu/odgren/51789900odgren/5