Correction
Authors: Reddy E. Premkumar 
Published: October 2006

In our report "Amplification and molecular cloning of HTLV-I sequences from DNA of multiple sclerosis patients", reference 16, which described the sequence and position of primers in the published HTLV-I sequence of Seiki
et al.
, contained three errors. (i) In the sequence given for one of the gag primers, a "C" was omitted. The actual sequence of the primer is 5′-CGACCGCCCCGGGGG
C
TGGCCGCT- 3′. The missing "C" in the published report is underlined. (ii) A second error occurred in the description of the position of the primers used for amplification of envelope sequences. The text should have read, "These primers would be expected to amplify the region between nucleotides 5662 to 6129 instead of 5684 to 6151." This confusion in numbering arose because the Los Alamos computer database on human retroviruses used a different numbering system, which we inadvertently used in describing the position of the primers and probes. (iii) In describing the reaction conditions, we inadvertently described the enzyme assay conditions provided by the manufacturer instead of the reaction conditions used for amplifications. The following restatement of reference 16 is correct.

16. The primers were derived from the
gag
and
env
regions of HTLV-I. The two
gag
primers were 5′- CGACCGCCCCGGGGGCTGGCCGCT-3′ and 5′- GGTACTGCAGGAGGTCTTGGAGG-3′. These primers would be expected to amplify the region between nucleotides 842 and 1375 of the sequence described by Seiki
et al.
This region corresponds to the region between nucleotides 863 and 1397 of the same sequence reported in the Los Alamos computer data base for human retroviruses (accession numbers J02029, K02722, J02028, J02030, J02031, and J02032). The oligonucleotide probe was 5′-GATCCCGTCCCGTCCCGCGCCA- 3′, which spans the region between nucleotides 1080 and 1101 of the published HTLV-I sequence (corresponding to 1102 and 1123 of the data base). The two
env
primers were 5′-CTCCCTTCTAGTCGACGCTCCAGG- 3′ and 5′-GCCACCGGTACCGCTCGGCGGGAG- 3′. These primers would be expected to amplify the region between nucleotides 5662 and 6129 of Seiki
et al.
(corresponding to nucleotides 5684 and 6151 of the database). The oligonucleotide probe was 5′-GCCTCICCACTTGGCACGTCC- 3', from nucleotides 5877 and 5897 (corresponding to nucleotides 5899 to 5919 of the data base). In some instances a nick-translated probe derived from the HTLV-I proviral genome that spanned the amplified region was used instead of the oligonucleotide probe. Amplification of the DNA was performed with the Geneamp kit provided by Perkin-Elmer Cetus Corp. (Norwalk, CT). The reactions were carried out with 2 μg of DNA and 1.0 ,umol of the primers under conditions modified from those specified by the manufacturer. The reaction mixtures contained 10 m
M
tris-HCl,
p
H 8.3; 50 m
M
KCl, 1.5 m
M
MgCl
2
, 0.01% gelatin, 200 μ
M
each of dATP, dGTP, TTP, and dCTP in a final volume of 100 μl. 2.5 units of
Taq
polymerase were used for each assay. Typically, for each cycle of amplification, the mixture was denatured at 94°C for 2 min, annealed at 55°C for 1 min, and then extended at 70°C for 2 min. From 36 to 40 cycles of amplification were performed and fresh enzyme (2 to 5 units) was added to each tube at the end of every tenth cycle."

In the text of the same paper, the fourth sentence of the fourth paragraph should have read, "These were 23-24 bases long and rich in G-C content to allow stable hybridization."