Mutations in the env gene of human immunodeficiency virus type 1 NDK isolates and the use of African green monkey CXCR4 as a co-receptor in COS-7 cells.

A previous report from this laboratory described the isolation of the first CD4-independent human immunodeficiency virus type 1 isolate, m7NDK. This independence of CD4 is due to seven mutations located in the C2, V3 and C3 regions of the gp120 protein. The present report describes the entry features of the m5NDK virus, which contains five of the seven m7NDK mutations, located in the V3 loop and C3 region.

Spontaneous mutations in the env gene of the human immunodeficiency virus type 1 NDK isolate are associated with a CD4-independent entry phenotype.

Human immunodeficiency virus type 1 (HIV-1) entry into target cells is a multistep process initiated by envelope protein gp120 binding to cell surface CD4. The conformational changes induced by this interaction likely favor a second-step interaction between gp120 and a coreceptor such as CXCR4 or CCR5. Here, we report a spontaneous and stable CD4-independent entry phenotype for the HIV-1 NDK isolate.

Molecular cloning and sequencing of a cDNA encoding a beta-thyroid hormone receptor in muscovy duckling.

A cDNA clone encoding a beta-thyroid hormone receptor (TRbeta) from muscovy duckling liver was isolated and sequenced. Comparison with the chicken TRbeta sequence showed a high degree of homology. This cDNA was used as a probe to characterize the TRbeta mRNA transcripts expressed in muscovy duckling liver.

Characterization of a cDNA encoding an alpha thyroid hormone receptor in muscovy duckling.

A complementary deoxyribonucleic acid (cDNA) clone encoding an alpha thyroid hormone receptor (TR alpha) from muscovy duckling liver was isolated and sequenced. Comparison with the chicken TR alpha sequence showed a high degree of homology. Despite 45 nucleotide substitutions, the deduced peptide sequence was similar.