PMID- 3120186
OWN - NLM
STAT- MEDLINE
DCOM- 19880107
LR  - 20190501
IS  - 0027-8424 (Print)
IS  - 1091-6490 (Electronic)
IS  - 0027-8424 (Linking)
VI  - 84
IP  - 23
DP  - 1987 Dec
TI  - Trypanosome mRNAs have unusual "cap 4" structures acquired by addition of a 
      spliced leader.
PG  - 8190-4
AB  - A single capped oligonucleotide is released from Trypanosoma brucei poly(A)+ RNA 
      upon digestion with RNase T2. This observation supports the hypothesis that all 
      T. brucei mRNAs share a common leader sequence. Digestion of the T2-resistant 
      species with nucleotide pyrophosphatase shows that the capping nucleotide is 
      7-methylguanosine 5'-monophosphate (pm7G). Additional characterization of the 
      T2-resistant fragment indicates that modifications are present on the first four 
      transcribed nucleotides; the 5' termini of T. brucei mRNAs can, therefore, be 
      described as "cap 4" structures. Identical 5'-cap structures are found on the T. 
      brucei spliced leader (SL) RNA; an observation compatible with the hypothesis 
      that the small SL RNA acts as a donor of the SL for the mRNA. However, we find 
      that within a population of purified SL RNAs are species that are capped but 
      incompletely modified. The presence of these unmodified and partially modified 
      species allowed us to analyze the 5' sequence of the SL RNA transcript. The 
      results indicate that transcription begins four nucleotides upstream of the 
      reported 5' end. Therefore, the T. brucei SL transcript is actually 39 rather 
      than 35 nucleotides long. We have also analyzed the capped oligonucleotide of a 
      distantly related Trypanosomatid, Leptomonas collosoma and find it to be 
      identical to that of T. brucei. The potential significance of these results is 
      discussed in light of observations of trypanosome gene expression.
FAU - Perry, K L
AU  - Perry KL
AD  - School of Public Health, University of California, Berkeley 94720.
FAU - Watkins, K P
AU  - Watkins KP
FAU - Agabian, N
AU  - Agabian N
LA  - eng
GR  - AI-21975/AI/NIAID NIH HHS/United States
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Proc Natl Acad Sci U S A
JT  - Proceedings of the National Academy of Sciences of the United States of America
JID - 7505876
RN  - 0 (RNA Caps)
RN  - 0 (RNA, Messenger)
SB  - IM
MH  - Animals
MH  - Base Sequence
MH  - Methylation
MH  - *RNA Caps
MH  - RNA Splicing
MH  - RNA, Messenger/genetics
MH  - Trypanosoma brucei brucei/*genetics
MH  - Trypanosomatina/*genetics
PMC - PMC299507
EDAT- 1987/12/01 00:00
MHDA- 1987/12/01 00:01
PMCR- 1988/06/01
CRDT- 1987/12/01 00:00
PHST- 1987/12/01 00:00 [pubmed]
PHST- 1987/12/01 00:01 [medline]
PHST- 1987/12/01 00:00 [entrez]
PHST- 1988/06/01 00:00 [pmc-release]
AID - 10.1073/pnas.84.23.8190 [doi]
PST - ppublish
SO  - Proc Natl Acad Sci U S A. 1987 Dec;84(23):8190-4. doi: 10.1073/pnas.84.23.8190.