Lentinanisanantitumorproductthatispurifiedfromfresh
Lentinulaedodesfruitingbodies.Itisacellwallcomponent,comprisingβ-1,3-glucanwithβ-1,6-linkedbranches,whichbecomesdegradedduringpostharvestpreservationasaresultofincreasedglucanaseactivity.Inthisstudy,weusedN-terminalaminoacidsequencetoisolate
tlg1,ageneencodingathaumatin-like(TL)proteinin
L.edodes.The
CDNAclonewasapproximately1.0kbwhereasthegenomicsequencewas2.1kb,andcomparisonofthetwoindicatedthat
tlg1contains12introns.The
tlg1geneproduct(TLG1)waspredictedtocomprise240aminoacids,withamolecularmassof25kDandisoelectricpointvalueof3.5.Theputativeaminoacidsequenceexhibitsapproximately40%identitywithplantTLproteins,andafungalgenomedatabasesearchrevealedthattheseTLproteinsareconservedinmanyfungiincludingthebasidiomycotaandascomycota.Transcriptionof
tlg1wasnotdetectedinvegetativemyceliumoryoungandfreshmushrooms.However,transcriptionincreasedfollowingharvest.Western-blotanalysisdemonstratedariseinTLG1levelsfollowingharvestandsporediffusion.TLG1expressedin
Escherichiacoliand
Aspergillusoryzaeexhibitedβ-1,3-glucanaseactivityand,whenpurifiedfromthe
L.edodesfruitingbody,demonstratedlentinandegr
ADIngactivity.Thus,wesuggestthatTLG1isinvolvedinlentinanandcellwalldegradationduringsenescencefollowingharvestandsporediffusion.