Structure and transcription of the actin gene of Trypanosoma brucei

Journal Article · Sun May 01 04:00:00 EDT 1988 · Mol. Cell. Biol.; (United States)

DOI:https://doi.org/10.1128/MCB.8.5.2166· OSTI ID:6945811

Ben Amar, M F; Pays, A; Tebabi, P; Dero, B; Seebeck, T; Steinert, M; Pays, E

In Trypanosoma brucei, the actin gene is present in a cluster of two, three, or four tandemly linked copies, depending on the strain. Each cluster seems to exist in two allelic versions, as suggested by the polymorphism of both gene number and restriction fragment length in the DNA from cloned trypanosomes. The amplification of the gene copy number probably occurs through unequal sister chromatic exchange. The chromosomes harboring the actin genes belong to the large size class. The coding sequence was 1,128 nucleotides long and showed 60 to 70% homology to other eucaryotic actin genes. Surprisingly, this homology seemed weaker with Trypanosoma congolense, Trypanosoma cruzi, Trypanosoma vivax, Trypanosoma mega, or Leishmania acting-specific sequences. The mRNA was around 1.6 kilobases long and was synthesized at the same level in bloodstream and procyclic forms of the parasite. Large RNA precursors, up to 7.7 kilobases, were found in a pattern identical in strains containing either two or three gene copies. Probing of the flanking regions of the gene with either steady-state or in vitro transcripts, as well as S1 nuclease protection and primer extension experiments, allowed mapping of the 3' splice site of the actin mRNA, 38 nucleotides upstream from the translation initiation codon. A variably sized poly(dT) tract was found about 30 base pairs ahead of the splice site. The largest detected actin mRNA precursor seemed to give rise to at least two additional stable mRNAs. The RNA polymerase transcribing the actin gene exhibited the same sensitivity to inhibition by ..cap alpha..-amanitin as that transcribing both the spliced leader and the bulk of polyadenylated mRNAs.

• Research Organization: Dept. of Molecular Biology, Univ. of Brussels, 67 rue des Chevaux, B1640 Rhode St. Genese (BE)
• OSTI ID: 6945811
• Journal Information: Mol. Cell. Biol.; (United States), Journal Name: Mol. Cell. Biol.; (United States) Vol. 8:5; ISSN MCEBD
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
550400 -- Genetics
59 BASIC BIOLOGICAL SCIENCES
ACTIN
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL FUNCTIONS
CODONS
CONTROL
ENZYMES
FUNCTIONS
GENES
GENETIC CONTROL
GENETIC MAPPING
KINETICS
MAPPING
MASTIGOPHORA
MESSENGER-RNA
NUCLEIC ACIDS
NUCLEOTIDES
NUCLEOTIDYLTRANSFERASES
ORGANIC COMPOUNDS
PARASITES
PEST CONTROL
PHOSPHORUS-GROUP TRANSFERASES
POLYMERASES
PRECURSOR
PROTEINS
REACTION KINETICS
RNA
RNA POLYMERASES
STRUCTURE-ACTIVITY RELATIONSHIPS
TRANSCRIPTION
TRANSFERASES
TRYPANOSOMA