Exploring the FL-160-CRP gene family through sequence variability of the complement regulatory protein (CRP) expressed by the trypomastigote stage of Trypanosoma cruzi /Mathieu-Daudé, Françoise /Lafay, Bénédicte Touzet, O. Lelievre, J. Parrado, F. /Bosseno, Marie-France Rojas, A. M. /Fatha, Salima /Ouaissi, Ali /Brenière, Simone Frédérique Trypanosoma cruzi complement regulatory protein FL 160 trans sialidase like proteins The complement regulatory protein (CRP) of Trypanosoma cruzi is a surface glycoprotein which confers to the infectious trypomastigote forms a protection against the lytic activity of the host complement. CRP belongs to the large family of the trans-sialidase-like proteins and its sequence is highly similar to those of the flagellar FL-160 and chronic exoantigen proteins, encoded by a multigene family. To further define the gene family encoding the CRP, we investigated the protein diversity among several strains of T cruzi through the sequencing of trypomastigote transcripts, and used a phylogenetic analysis based on the multiple alignment of these proteins with the top scoring sequences detected by a database sequence homology search. Intrastrain variations in CRP sequences revealed the existence of several copies per strain. The interstrain variability of CRP was consistent with the genetic subdivisions of T cruzi into lineages and discrete typing units. The phylogenetic analysis based on a 227 amino acid alignment of CRP sequences with the 200 putative proteins retrieved from the protein databases (including the sequences from the T cruzi genome project) revealed that the CRP sequences clustered with the FL-160 proteins into a monophyletic group characterized by the presence of the 12 amino acid mimicry epitope that mimics nervous tissues. The phylogeny did not differentiate between the CRP and the FL-160 proteins. The identification of this group of CRP-like proteins and the high sequence similarity observed within it open up new prospects for the exploration of the localization, structure and function of these proteins and a better understanding of their involvement in key aspects of host-parasite interactions, such as the resistance to the complement. This work provides also information for the T cruzi genome annotation of the trans-sialidase-like putative proteins. 2008 text https://www.documentation.ird.fr/hor/fdi:010042624 fdi:010042624 Mathieu-Daudé Françoise, Lafay Bénédicte, Touzet O., Lelievre J., Parrado F., Bosseno Marie-France, Rojas A. M., Fatha Salima, Ouaissi Ali, Brenière Simone Frédérique. Exploring the FL-160-CRP gene family through sequence variability of the complement regulatory protein (CRP) expressed by the trypomastigote stage of Trypanosoma cruzi. 2008, 8 (3), 258-266 EN