Shardell Hawkins-Spriggs, Ph.D.


Biochemistry 2008

Area of Doctoral Study: Biochemistry
Undergraduate Institution: University of Maryland, Eastern Shore

Research Advisor: Michael Summers, Ph.D.

Current Position: Staff Scientist, National Institutes of Health (NIH)

Description of Research

The Human Immunodeficiency Virus (HIV-1) packages its genome by specific interactions between the NC domain of Gag and a ~120 nucleotide region of the unspliced viral RNA, known as the psi-site, located between the 5¹ LTR and the gag initiation site. The HIV-1 psi-site contains four stem loop structures designated SL1 through SL4, connected by relatively short linkers. Stem loops SL1 and SL2 contain the dimer initiation site and the major splice donor site, respectively, and SL4 contains the gag initiation condon. Molecular biological and biochemical data indicate that all four stem loops of the HIV-1 psi-site are important for efficient encapsidation, and, in fact, they may serve redundant roles in RNA packaging. Although the secondary structure elements of the HIV-1 psi-site have been characterized, little is known about the globular fold of the intact RNA. Indeed, RNA encapsidation appears to be dependent on a higher order RNA structure. We have established that dimerization is concentration dependent and increased ionic strength also induces dimerization. We are probing the structure of the psi-site by multidimensional NMR methods.