Repetitive sequences upstream of the pfg27/25 gene determine polymorphism in laboratory and natural lines of Plasmodium falciparum

Pina Sallicandro, Maria Grazia Paglia, Suhaila Omar Hashim, Francesco Silvestrini, Leonardo Picci, Marco Gentile, Francis Mulaa, Pietro Alano

Research output: Contribution to journalArticle

Abstract

The structure of the genomic region located upstream of the gametocyte-specific gene pfg27/25 of Plasmodium falciparum was analysed in laboratory lines and field isolates of the parasite. The gene is located in a subtelomeric region of chromosome 13 in parasite clones 3D7 and HB3. Analysis of laboratory lines and field isolates of P. falciparum indicated that polymorphism upstream of pfg27/25 is mainly due to the structure of a repetitive DNA region located at about half a kilobase from the pfg27/25 coding sequence. Different types of repetitive sequences are present in this region, whose copy number is variable in different parasite lines. In addition a GC-rich sequence element contained in this region, which is proposed to be the startpoint of pfg27/25 mRNA, presents either a direct or a reverse orientation in different parasite lines. Genomic deletions upstream of the pfg27/25 gene are also described in two laboratory lines of the parasite, which eliminate two newly identified malaria genes, orf P and orf Gap, from the genome of these parasites. One of them, orf Gap, deleted from the reference parasite clone 3D7, is abundantly expressed as mature mRNA in asexual parasites. PCR analysis on 64 field isolates of P. falciparum indicated that orf P and orf Gap sequences are present in all tested samples of naturally propagating parasites. (C) 2000 Elsevier Science B.V.

Original languageEnglish
Pages (from-to)247-257
Number of pages11
JournalMolecular and Biochemical Parasitology
Volume110
Issue number2
DOIs
Publication statusPublished - 2000

Keywords

  • Genetic polymorphism
  • Genomic rearrangement
  • Malaria
  • P. falciparum
  • Repetitive DNA sequences

ASJC Scopus subject areas

  • Molecular Biology
  • Parasitology

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