Re: Without the “HIV” genome (poly (A)-RNA banding at 1.16 g/ml) there can be no probes or molecular clones 2 July 2004
Previous Rapid Response Next Rapid Response Top
Brian T Foley,
HIV Researcher
Los Alamos National Lab, Los Alamos, NM 87545

Send response to journal:
Re: Re: Without the “HIV” genome (poly (A)-RNA banding at 1.16 g/ml) there can be no probes or molecular clones

The Perth group wrote:
“…
Without the “HIV” genome (poly (A)-RNA banding at 1.16 g/ml) there can be no probes or molecular clones
…”

This is not quite true, there are other ways to make probes, and banded virus is definitely not needed to obtain proviral clones. For example, if simian immunodeficiency viruses had already been cloned prior to 1983 and researchers had suspected that AIDS might be caused by a similar virus, they could have used the gene regions from the simian virus as probes.

At any rate, this is a moot point because the first groups studying HIV-1 all used genomes banded in sucrose gradients as their probes.

The Perth group wrote:
“…
We would be grateful if Brian Foley would answer our question regarding the two poly(A)-RNAs, that is, the “HIV-1” genome which bands at 1.16g/ml and the “HIV-1” genome from which the proviral DNA was obtained. Are these two poly(A)-RNAs the same?
…”

They are similar, but not 100% identical. The genome in the 1.16 g/ml band is indeed polyadenylated RNA. The proviral genome integrated into host cells does not have a poly-A tail, and is DNA, not RNA. The Long Terminal repeats are present in 2 complete copies in integrated proviral DNA, whereas the LTRs found in packaged genomes begins at the 5’ R region end ends at the 3’ R region. The packaged RNA genome thus lacks the 5’ U3 region and the 3’ U5 region of the LTRs.

The Perth group wrote:
“…
It is a pity that Brian Foley again sidesteps the question and gives us an irrelevant oration. The question has nothing to do with Luc Montagnier’s work. The two clones were obtained by Gallo and his associates, not by Montagnier. Most importantly, we did not ask from which patient(s) the clones originated from.
…”

The answer was VERY pertinent. The investigation into Gallo’s and Montagnier’s groups discovery of HIV-1 M group subtype B in AIDS patients but not in healthy individuals not at risk for AIDS determined that Gallo’s group had obtained viral samples and/or cell cultures from Montagnier’s group. It turned out that the Lambda-HXB2 clone from Gallo and the LAV clones from Montagnier were derived from the very same patient.

The Perth group wrote:
“…
1. Was the ultimate origin of the two clones the “HIV provirus”?
…”

Yes. The Lambda-HXB2 and Lambda-HXB3 clones came from proviral DNA integrated into host cell DNA. The Lambda-BH10 clones came from unintegrated circular proviral DNA. The Lambda-J19 and Lambda-J81 clones were from integrated proviral DNA.

The Perth group wrote:
“…
2. Was the provirus obtained from a poly(A)-RNA that was the same as the poly(A)-RNA (the “HIV-1” genome) which, in sucrose gradients, banded at 1.16g/ml?
…”

Yes, the proviruses were reverse transcribed by the viral RT, copied into double-stranded DNA by a cellular polymerase, and integrated into the human cell genome by the viral integrase.

Competing interests: None declared