Developmental changes in the adhesive disk during Giardia differentiation.
Giardia lamblia is a protozoan parasite infecting the upper mammalian small intestine. Infection relies upon the ability of the parasite to attach to the intestine via a unique cytoskeletal organelle, the ventral disk. We determined the composition and structure of the disk throughout the life cycle of the parasite and identified a new disk protein, SALP-1. SALP-1 is an immunodominant protein related to striated fiber-assemblin (SFA). The disk is disassembled during encystation and stored as four fragments in the immobile cyst. Serial Analysis of Gene Expression (SAGE) showed that the mRNA levels of the disk proteins decreased in encystation but two-dimensional protein gels showed that the protein levels were more constant. The parasite emerges without a functional disk but the four disk fragments are quickly reassembled into two new disks on the dividing, early excysting form. Thus, disk proteins are stored within the cyst, ready to be used in the rapid steps of excystation.
Palm
Daniel
D
Microbiology and Tumor Biology Center, Karolinska Institutet, SE-171 77 Stockholm, Sweden.
Weiland
Malin
M
McArthur
Andrew G
AG
Winiecka-Krusnell
Jadwiga
J
Cipriano
Michael J
MJ
Birkeland
Shanda R
SR
Pacocha
Sarah E
SE
Davids
Barbara
B
Gillin
Frances
F
Linder
Ewert
E
Svärd
Staffan
S
D000595:Amino Acid Sequence; D000818:Animals; D015180:Electrophoresis, Gel, Two-Dimensional; D005786:Gene Expression Regulation; D018507:Gene Expression Regulation, Developmental; D016829:Giardia lamblia / Q000166:cytology / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D008969:Molecular Sequence Data; D009024:Morphogenesis; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D016053:RNA, Protozoan / Q000032:analysis; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D015800:Protozoan Proteins; D012333:RNA, Messenger; D016053:RNA, Protozoan