X-ray crystallographic studies of RoAb13 bound to PIYDIN, a part of the N-terminal domain of C-C chemokine receptor 5

C-C chemokine receptor 5 (CCR5) is a major co-receptor molecule used by HIV-1 to enter cells. This led to the hypothesis that stimulating an antibody response would block HIV with minimal toxicity. Here, X-ray crystallographic studies of the anti-CCR5 antibody RoAb13 together with two peptides were undertaken: one peptide is a 31-residue peptide containing the PIYDIN sequence and the other is the PIDYIN peptide alone, where PIYDIN is part of the N-terminal region of CCR5 previously shown to be important for HIV entry. In the presence of the longer peptide (the complete N-terminal domain), difference electron density was observed at a site within a hypervariable CDR3 binding region. In the presence of the shorter core peptide PIYDIN, difference electron density is again observed at this CDR3 site, confirming consistent binding for both peptides. This may be useful in the design of a new biomimetic to stimulate an antibody response to CCR5 in order to block HIV infection

Enhanced green fluorescent protein expression in the () adult zebrafish retina

Enhanced green fluorescent protein (EGFP; ), proliferating cell nuclear antigen (PCNA; ), Pax6 (), glutamine synthetase (GS; ), and merged expression () are shown. EGFP and PCNA are strongly expressed in the cells of the adult retinal circumferential marginal zone (CMZ; ). EGFP expression in the peripheral CMZ co-labels with Pax6 (*), but does not co-label near the distal CMZ (, arrow). The Pax6-positive EGFP-negative signal adjacent to the CMZ (arrowheads) corresponds to the newly differentiated amacrine and ganglion cells. EGFP is also expressed in PCNA-positive rod precursor cells, which reside in the outer nuclear layer (). Some of these rod precursor cells express high levels of EGFP (arrows), while others express lower EGFP levels (arrowhead). EGFP is also expressed in a row of nonproliferative PCNA-negative short single cones (). Some Müller glia in the adult undamaged retina slowly divide and give rise to retinal progenitor cells. PCNA marks these proliferating Müller glial cells, which also coexpress EGFP (, arrows). EGFP-positive cells in the INL also co-label with glutamine synthetase (, arrow). This demonstrates that proliferating EGFP-positive cells co-label with Müller glia. Abbreviations: ONL represents outer nuclear layer; INL represents inner nuclear layer; and GCL represents ganglion cell layer.<p><b>Copyright information:</b></p><p>Taken from "The () transgenic zebrafish line labels proliferating cells during retinal development and regeneration"</p><p></p><p>Molecular Vision 2008;14():951-963.</p><p>Published online 19 May 2008</p><p>PMCID:PMC2391084.</p><p></p

Enhanced green fluorescent protein expression in the light-damaged zebrafish retina

To initiate the regeneration response, dark-adapted adult () zebrafish were exposed to constant, high-intensity light to induce photoreceptor apoptosis. At 48 h of constant light exposure, enhanced green fluorescent protein (EGFP) is expressed in proliferating cell nuclear antigen (PCNA)-positive inner nuclear layer (INL) cells (). EGFP expression is also observed in Müller glial cell processes (arrows). At 48 h of light damage, Müller glia are labeled with glutamine synthetase (GS; ). All the EGFP-positive cells co-label with glutamine synthetase expressing Müller glia (). At 72 h of light damage, there are clusters of PCNA-positive neuronal progenitor cells associated with and migrating along Müller glia (). These cells express EGFP at a high intensity. () A higher magnification of the migrating progenitor cells at 72 h of light damage reveals that EGFP is expressed throughout the glial cell (). This is evident by labeling in the glial cell processes (arrows). There are multiple PCNA-positive progenitors that are also expressing EGFP (arrowheads). Abbreviations: GS represents glutamine synthetase; PCNA represents proliferating cell nuclear antigen; EGFP represents enhanced green fluorescent protein; ONL represents outer nuclear layer; INL represents inner nuclear layer; and GCL represents ganglion cell layer.<p><b>Copyright information:</b></p><p>Taken from "The () transgenic zebrafish line labels proliferating cells during retinal development and regeneration"</p><p></p><p>Molecular Vision 2008;14():951-963.</p><p>Published online 19 May 2008</p><p>PMCID:PMC2391084.</p><p></p

Enhanced green fluorescent protein expression during retinal development in zebrafish

Enhanced green fluorescent protein (EGFP; ), proliferating cell nuclear antigen (PCNA; ), and merged expression patterns () are shown at 54 hpf, 72 hpf, and 96 hpf of retinal development. At 54 hpf, EGFP is expressed throughout the entire retina, while PCNA expression is lower in the central retina relative to the retinal margin (). At 72 hpf, EGFP continues to be expressed throughout the central retina, while PCNA expression is largely absent in the central retina and highly expressed in the cells near the margin (). By 96 hpf, EGFP expression decreases in the central retina but remains in the margin, while PCNA expression remains restricted to the retinal margin ().<p><b>Copyright information:</b></p><p>Taken from "The () transgenic zebrafish line labels proliferating cells during retinal development and regeneration"</p><p></p><p>Molecular Vision 2008;14():951-963.</p><p>Published online 19 May 2008</p><p>PMCID:PMC2391084.</p><p></p