Fig 1.
PTBP domain organization and amino acid sequence alignment.
(top) A schematic representation of PTB protein indicating each distinct region. (bottom) Amino acid sequence alignment of human PTBP1 (isoform 4) and PTBP2. Gray boxes indicate RNA binding domains. Lines above the sequence indicate RNA interacting residues. Red triangles below the sequence indicate RNA interacting residues that are conservative substitutions in PTBP2. Gaps are indicated as dashes (-) in the alignment.
Fig 2.
Purification of His-6 tagged PTBP from splicing reaction mixtures.
Splicing reaction mixtures contained 2.2mM MgCl2, 0.4mM ATP and 20mM Creatine Phosphate and either HeLa nuclear extract or Buffer DG. Aliquots (10 μl) of the indicated fractions were analyzed by SDS-PAGE. The gel was stained with Gel Code blue safe stain. The positions and sizes (kilodaltons) of marker polypeptides are shown on the left.
Fig 3.
Heat map depicting the relative prevalence of the 17 proteins pulled down with both PTBP1 and PTBP2.
The 0 baseline, indicated by black color shading, was determined by taking the average of the area scores for all 17 proteins. Proteins with a higher or lower area score than this average are shaded green or red respectively, with each point on the scale indicating the number of standard deviations from the baseline. This heat map was generated via heatmapper.ca [31].
Fig 4.
Log fractional difference of observed vs expected GO SLIM biological process categories assigned to proteins found unique to the PTBP1 pulldown.
The log fractional difference is calculated for each category as (# genes for the category—# genes expected) / # genes expected) as provided on Gene Ontology.