title: Characterization of DNA sequences that confer complement resistance in Leishmania chagasi.
abstract: Serial passage of axenically cultured Leishmania chagasi promastigotes results in a progressive diminution in resistance to complement-mediated lysis (CML), whereas high CML resistance is seen in infectious metacyclic promastigotes from the sandfly vector as well as metacyclic-like promastigotes within low-passage cultures at stationary growth phase. As we previously reported, in a screen seeking to identify novel genes involved in CML resistance: (1) a genomic cosmid library derived from DNA of CML-resistant L. chagasi promastigotes was transfected into high-passage (constitutively CML-sensitive) L. chagasi promastigotes; (2) transformants were screened for acquisition of CML-resistance; (3) multiple cosmid-transfectants exhibited partial CML resistance; and (4) the sequence for one of the cosmids (Cosmid 51) was determined. This report extends the analysis of Cosmid 51, and identifies by deletion analysis a subregion of the cosmid insert that is critical to the CML-resistance phenotype of Cosmid 51 transformants. We also report the sequence determination and initial CML-resistance activity of another cosmid that also confers partial resistance to CML.
authors.affiliation: Department of Veterinary Pathology, Iowa State University, Ames, Iowa, USA.
authors.forename: Rebecca R
authors.initials: RR
authors.lastname: Dahlin-Laborde
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Scolaro
authors.forename: Nathan M
authors.initials: NM
authors.lastname: Romine
authors.forename: Amanda E
authors.initials: AE
authors.lastname: Ramer-Tait
authors.forename: Soi Meng
authors.initials: SM
authors.lastname: Lei
authors.forename: Jeffrey K
authors.initials: JK
authors.lastname: Beetham
mesh_terms: D000818:Animals; D003165:Complement System Proteins / Q000502:physiology*; D003360:Cosmids; D016054:DNA, Protozoan / Q000235:genetics*; D007891:Leishmania / Q000235:genetics*
chemical_list: D016054:DNA, Protozoan; D003165:Complement System Proteins