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G Kendall

Publications and source records attributed to G Kendall.

23 records · Page 2Linked to original sources
PubMed1991

The actin gene promoter of Trypanosoma brucei.

The actin genes of Trypanosoma brucei are transcribed constitutively during the parasite life-cycle, by a polymerase sensitive to alpha-amanitin. The start region of the actin gene transcription unit was mapped by virtue of the accumulation of promoter-proximal transcripts which occurs following moderate UV irradiation. This region, located about 4 kilobases upstream from the genes, was able to direct transient expression of the bacterial Chloramphenicol Acetyl Transferase (CAT) gene in both bloodstream and procyclic forms of the parasite. The essential region of the promoter was defined by deletion, and appeared to be within 600 bp upstream from the putative transcription start site. It does not share significant homology with the other trypanosome promoters described so far (VSG, procyclin, rDNA), which all direct alpha-amanitin resistant transcription.

Actins↗
PubMed1991

Trypanosoma brucei glycosomal glyceraldehyde-3-phosphate dehydrogenase genes are stage-regulated at the transcriptional level.

Regions 5' of the glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH) gene from Trypanosoma brucei were tested for their ability to promote chloramphenicol acetyl-transferase (CAT) expression on reintroduction by electroporation into the parasite. Deletion analysis mapped the gGAPDH promoter to within 403 nts of the start of translation. A transcription initiation site was mapped at around -190 nts from the ATG start codon by RNase protection and by primer extension. The higher expression of gGAPDH in bloodstream T. brucei, compared to procyclic (insect) forms, was largely attributed to differences in promoter activity. The gGAPDH promoter gave rise to relatively high CAT signals upon transfection into bloodstream T. brucei and relatively low signals in procyclic T. brucei, compared with levels resulting from transfection with the procyclic acidic repetitive protein (PARP) promoter. In addition, RNase protection data showed a higher level of gGAPDH primary transcripts in bloodstream. T. brucei. The PARP mini-exon addition region abolished transient CAT expression directed by either the gGAPDH or PARP promoters in bloodstream T. brucei implying that transplicing can be a point of stage-specific gene regulation.

Animals↗
PubMed1990

Trypanosoma cruzi glycosomal glyceraldehyde-3-phosphate dehydrogenase does not conform to the 'hotspot' topogenic signal model.

The genes which encode glycosomal glyceraldehyde-phosphate dehydrogenase (gGAPDH) of Trypanosoma cruzi are arranged as a tandemly repeated pair on a single chromosome and are identical at the level of nucleotide sequence. They are separated by an intergenic region which contains a 317 base pair sequence with the properties of a retroposon. The genes express a 1.5 kb mRNA and a 38 kd protein. The amino acid sequence contains features characteristic of glycosomal enzymes such as peptide insertions and a C-terminal extension. However, T. cruzi gGAPDH lacks one of the positively charged 'hotspot' motifs which have been proposed as topogenic signals for import into the glycosome, a unique microbody-like organelle. Molecular modelling of the T. cruzi and T. brucei enzymes suggests that neither structure would fulfil the requirements of the 'hotspot' glycosomal import model.

Amino Acid Sequence↗