Functional screening

Functional screening of a soil metagenomic library for cellulases revealed a total of eight cellulolytic clones, one of which was purified and characterized [58]. Despite the fact that this library had been generated from a soil sample collected from a... 

Snodin, D.J., Regulatory immunotoxicology does the published evidence support mandatory nonclinical immune function screening in drug development , Regul. Toxicol. Pharmacol., 40, 336, 2004. 

Figure 2.3 Metagenomic cloning experiments. Isolation of genomic DNA directly from environments (soil, plants, mixed environments or thermal-vent worms are the examples Illustrated here) can recover DNA fragments which could encode for enzymes. The DNA fragments can be ligated to plasmids or DNA linkers, and then subjected to functional screening (expression cloning) and/or sequence analysis. Amplification by PCR can sometimes be used to yield libraries enriched with clones containing selected sequence motifs relating to families of enzymes...

FUNCTIONAL SCREEN (protein purification, expression cloning)... 

Fig. 2 Yeast-based functional screen for receptor-independent activators of G-protein signaling. The yeast strain indicated in A was generated as described previously (Cismowski et al. 1999, 2002) and transformed with mammalian cDNA libraries in the galactose-inducible yeast expression vector pYES2. The strategy for identifying mammalian cDNAs that promoted growth (i.e., activated G-protein signaling pathway) is indicated in B. GALlp GALl promoter)...

Fig. 3 A AGS proteins isolated in yeast-based functional screen G-protein signaling modulator (GPSM) as named by the Human Genome Nomenclature Committee. The major sites of action of AGS proteins in the context of the G-protein activation-deactivation cycle are indicated B on the right. (GPR G-protein regulatory, GEF guanine nucleotide exchange factor, GDI guanine nucleotide dissociation inhibitor, GPCR G-protein coupled receptor)...

Cismowski MJ, Takesono A, Ma C, Lanier SM, Duzic E (2002) Identification of modulators of mammalian G-protein signaUng by functional screens in the yeast Saccharomyces cerevisiae. Methods Enzymol 344 153-168... 

Drug Discovery Through Functional Screening in the Drosophila Heart... 

Various on-bead binding or functional screening methods for OBOC combinatorial libraries are described in Chapter 17 in this volume and will not be repeated here. The positive beads are physically isolated under a microscope for structure determination. 

Kassack, M.U. et al. 2002. Functional screening of G protein-coupled receptors by measuring intracellular calcium with a fluorescence microplate reader. J. Biomol. Screen. 7, 233-246. 

---