Comprehensive characterization of Cysteine-rich protein-coding genes of Giardia lamblia and their role during antigenic variation

RODRÍGUEZ-WALKER, MACARENA; MOLINA, CECILIA R.; LUJÁN, LUCAS A.; SAURA, ALICIA; FERNÁNDEZ, ELMER A.; LUJÁN, HUGO D.

GENOMICS

ACADEMIC PRESS INC ELSEVIER SCIENCE

Año: 2022

0888-7543

Giardia lamblia encodes several families of cysteine-rich proteins, including the Variantspecific Surface Proteins (VSPs) involved in the process of antigenic variation. Theircharacteristics, definition and relationships are still controversial. An exhaustive analysis ofthe Cys-rich families including organization, features, evolution and levels of expressionwas performed, by combining pattern searches and predictions with massive sequencingtechniques. Thus a new classification for Cys-rich proteins, genes and pseudogenes thatbetter describes their involvement in Giardia’s biology is presented. Moreover, three novelcharacteristics exclusive to the VSP genes, comprising an Initiator element/Kozak-likesequence, an extended polyadenylation signal and a unique pattern of mutually exclusivetranscript accumulation is presented as well as the finding that High Cysteine MembraneProteins, upregulated under stress, may protect the parasite during VSP switching. Theseresults allow better interpretation of previous reports providing the basis for further studiesof the biology of this early-branching eukaryote.