TY - JOUR
T1 - Characterization of a retrotransposon-like element from Entamoeba histolytica
AU - Sharma, Rachna
AU - Bagchi, Anindya
AU - Bhattacharya, Alok
AU - Bhattacharya, Sudha
PY - 2001
Y1 - 2001
N2 - The protozoan parasite Entamoeba histolytica is the causative agent of amoebiasis. The genome organization of this organism is not well understood. We had earlier reported the presence of a multicopy sequence, HMc, in E. histolytica. Subsequent analysis showed that HMc is a member of a retrotransposon family that we have named the E. histolytica retrotransposon-like element (EhRLE). Four other members of this family have been characterized. The EhRLE family is distributed across all chromosomes of the parasite. There are 140 copies, which show minor sequence variation with respect to one another (2-4% from the consensus sequence). From a sequence analysis of five members of the EhRLE family, the complete EhRLE unit is estimated to be 4086 bp in length. It has a 27-mer inverted repeat at its ends. A pairwise comparison with sequences in the database showed a highly significant match of a part of EhRLE with reverse transcriptases (RT), especially those encoded by non-long terminal repeat retrotransposons. There are stop codons in all the five EhRLEs, but a continuous open reading frame of 464 amino acids could be reconstructed by comparing the sequences of several EhRLEs. The reconstructed sequence showed a much better identity with RT as compared with any of the original EhRLE sequences. The non-pathogenic species, Entamoeba dispar, also contains this element, with 85% sequence identity with EhRLE. The data suggest that EhRLE may be a retrotransposon, but many of its members are probably nonfunctional due to the accumulation of mutations.
AB - The protozoan parasite Entamoeba histolytica is the causative agent of amoebiasis. The genome organization of this organism is not well understood. We had earlier reported the presence of a multicopy sequence, HMc, in E. histolytica. Subsequent analysis showed that HMc is a member of a retrotransposon family that we have named the E. histolytica retrotransposon-like element (EhRLE). Four other members of this family have been characterized. The EhRLE family is distributed across all chromosomes of the parasite. There are 140 copies, which show minor sequence variation with respect to one another (2-4% from the consensus sequence). From a sequence analysis of five members of the EhRLE family, the complete EhRLE unit is estimated to be 4086 bp in length. It has a 27-mer inverted repeat at its ends. A pairwise comparison with sequences in the database showed a highly significant match of a part of EhRLE with reverse transcriptases (RT), especially those encoded by non-long terminal repeat retrotransposons. There are stop codons in all the five EhRLEs, but a continuous open reading frame of 464 amino acids could be reconstructed by comparing the sequences of several EhRLEs. The reconstructed sequence showed a much better identity with RT as compared with any of the original EhRLE sequences. The non-pathogenic species, Entamoeba dispar, also contains this element, with 85% sequence identity with EhRLE. The data suggest that EhRLE may be a retrotransposon, but many of its members are probably nonfunctional due to the accumulation of mutations.
KW - Entamoeba histolytica
KW - Non-long terminal repeat
KW - Retrotransposons
KW - Reverse transcriptase
UR - http://www.scopus.com/inward/record.url?scp=0034884407&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0034884407&partnerID=8YFLogxK
U2 - 10.1016/S0166-6851(01)00300-0
DO - 10.1016/S0166-6851(01)00300-0
M3 - Article
C2 - 11463465
AN - SCOPUS:0034884407
VL - 116
SP - 45
EP - 53
JO - Molecular and Biochemical Parasitology
JF - Molecular and Biochemical Parasitology
SN - 0166-6851
IS - 1
ER -