title: Expression and subcellular localization of kinetoplast-associated proteins in the different developmental stages of Trypanosoma cruzi.
abstract: BACKGROUND
  The kinetoplast DNA (kDNA) of trypanosomatids consists of an unusual arrangement of circular molecules catenated into a single network. The diameter of the isolated kDNA network is similar to that of the entire cell. However, within the kinetoplast matrix, the kDNA is highly condensed. Studies in Crithidia fasciculata showed that kinetoplast-associated proteins (KAPs) are capable of condensing the kDNA network. However, little is known about the KAPs of Trypanosoma cruzi, a parasitic protozoon that shows distinct patterns of kDNA condensation during their complex morphogenetic development. In epimastigotes and amastigotes (replicating forms) the kDNA fibers are tightly packed into a disk-shaped kinetoplast, whereas trypomastigotes (non-replicating) present a more relaxed kDNA organization contained within a rounded structure. It is still unclear how the compact kinetoplast disk of epimastigotes is converted into a globular structure in the infective trypomastigotes.
  
  
  RESULTS
  In this work, we have analyzed KAP coding genes in trypanosomatid genomes and cloned and expressed two kinetoplast-associated proteins in T. cruzi: TcKAP4 and TcKAP6. Such small basic proteins are expressed in all developmental stages of the parasite, although present a differential distribution within the kinetoplasts of epimastigote, amastigote and trypomastigote forms.
  
  
  CONCLUSIONS
  Several features of TcKAPs, such as their small size, basic nature and similarity with KAPs of C. fasciculata, are consistent with a role in DNA charge neutralization and condensation. Additionally, the differential distribution of KAPs in the kinetoplasts of distinct developmental stages of the parasite, indicate that the kDNA rearrangement that takes place during the T. cruzi differentiation process is accompanied by TcKAPs redistribution.
authors.affiliation: Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. danic@biof.ufrj.br
authors.forename: Danielle Pereira
authors.initials: DP
authors.lastname: Cavalcanti
authors.forename: Márcia Kiyoe
authors.initials: MK
authors.lastname: Shimada
authors.forename: Christian Macagnan
authors.initials: CM
authors.lastname: Probst
authors.forename: Thais Cristina Baeta Soares
authors.initials: TC
authors.lastname: Souto-Padrón
authors.forename: Wanderley
authors.initials: W
authors.lastname: de Souza
authors.forename: Samuel
authors.initials: S
authors.lastname: Goldenberg
authors.forename: Stênio Perdigão
authors.initials: SP
authors.lastname: Fragoso
authors.forename: Maria Cristina Machado
authors.initials: MC
authors.lastname: Motta
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D018105:DNA, Kinetoplast / Q000235:genetics; D016054:DNA, Protozoan / Q000235:genetics; D018503:Genome, Protozoan; D008018:Life Cycle Stages / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D026801:Synteny; D014349:Trypanosoma cruzi / Q000235:genetics / Q000378:metabolism*
chemical_list: D018105:DNA, Kinetoplast; D016054:DNA, Protozoan; D015800:Protozoan Proteins; D011994:Recombinant Proteins