Skip to main content
padlock icon - secure page this page is secure

Free Content Developmental gene regulation in Giardia lamblia: first evidence for an encystation-specific promoter and differential 5′ mRNA processing

Download Article:
 Download
(PDF)
 
Giardia lamblia must encyst to survive in the environment and subsequently infect new hosts. We investigated the expression of glucosamine-6-phosphate isomerase (Gln6PI), the first enzyme required for biosynthesis of N-acetylgalactosamine, for the major cyst wall polysaccharide. We isolated two Gln6PI genes that encode proteins with large areas of identity, but distinctive central and terminal regions. Both recombinant enzymes have comparable kinetics. Interestingly, these genes have distinct patterns of expression. Gln6PI-A has a conventional, short 5′ untranslated region (UTR), and is expressed at a low level during vegetative growth and encystation. The Gln6PI-B gene has two transcripts — one is expressed constitutively and the second species is highly upregulated during encystation. The non-regulated Gln6PI-B transcript has the longest 5′-UTR known for Giardia and is 5′ capped or blocked. In contrast, the Gln6PI-B upregulated transcript has a short, non-capped 5′-UTR. A small promoter region (< 56 bp upstream from the start codon) is sufficient for the regulated expression of Gln6PI-B. Gln6PI-B also has an antisense overlapping transcript that is expressed constitutively. A shorter antisense transcript is detected during encystation. This is the first report of a developmentally regulated promoter in Giardia, as well as evidence for a potential role of 5′ RNA processing and antisense RNA in differential gene regulation.
No References
No Citations
No Supplementary Data
No Article Media
No Metrics

Document Type: Research Article

Affiliations: 1: Division of Infectious Diseases, Department of Pathology, University of California at San Diego, 214 Dickinson St., San Diego, CA 92103-8416, USA., 2: The Josephine Bay-Paul Center of Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, MA 02543-1015, USA.,

Publication date: October 1, 1999

  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
X
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more