title: Structure and regulation of histone H2B mRNAs from Leishmania enriettii.
abstract: We have studied the structure and expression of histone H2B mRNA and genes in the parasitic protozoan Leishmania enrietti. A genomic clone containing three tandemly repeated genes has been sequenced and shown to encode three identical histone proteins and two types of closely related mRNA sequence. We have also sequenced three independent cDNA clones and demonstrated that the Leishmania H2B mRNAs are polyadenylated, similar to the basal histone mRNAs of higher eucaryotes and the histone mRNAs of yeast. In addition, the Leishmania mRNAs contain inverted repeats near the poly(A) tail which could form stem-loops similar in secondary structure, but not in sequence, to the 3' stem-loops of nonpolyadenylated replication-dependent histones of higher eucaryotes. Unlike the replication-dependent histones, the Leishmania histone H2B mRNAs do not decrease in abundance following treatment with inhibitors of DNA synthesis. The histone mRNAs are differentially expressed during the parasite life cycle and accumulate to a higher level in the extracellular promastigotes (the form which in nature lives within the gut of the insect vector) than in the intracellular amastigotes (the form that lives within the mammalian host macrophages).
authors.affiliation: Department of Microbiology and Immunology, Oregon Health Sciences University, Portland 97201.
authors.forename: J E
authors.initials: JE
authors.lastname: Genske
authors.forename: B R
authors.initials: BR
authors.lastname: Cairns
authors.forename: S P
authors.initials: SP
authors.lastname: Stack
authors.forename: S M
authors.initials: SM
authors.lastname: Landfear
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D003001:Cloning, Molecular; D004247:DNA; D016054:DNA, Protozoan / Q000235:genetics; D015870:Gene Expression; D005796:Genes; D006657:Histones / Q000235:genetics*; D006860:Hydrogen Bonding; D007894:Leishmania mexicana / Q000235:genetics*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012333:RNA, Messenger / Q000235:genetics*; D016053:RNA, Protozoan / Q000235:genetics; D015183:Restriction Mapping
chemical_list: D016054:DNA, Protozoan; D006657:Histones; D012333:RNA, Messenger; D016053:RNA, Protozoan; D004247:DNA