Comparison of TRIBE and STAMP for identifying targets of RNA binding proteins in human and Drosophila cells

RNA binding proteins (RBPs) perform a myriad of functions and are implicated in numerous neurological diseases. To identify the targets of RBPs in small numbers of cells, we developed TRIBE, in which the catalytic domain of the RNA editing enzyme ADAR (ADARcd) is fused to a RBP. When the RBP binds to a mRNA, ADAR catalyzes A to G modifications in the target mRNA that can be easily identified in standard RNA-sequencing. In STAMP, the concept is the same except the ADARcd is replaced by the RNA editing enzyme APOBEC. Here we compared TRIBE and STAMP side-by-side in human and Drosophila cells. The goal is to learn the pros and cons of each method so that researchers can choose the method best suited to their RBP and system. In human cells, TRIBE and STAMP were performed using the RBP TDP-43. Although they both identified TDP-43 target mRNAs, combining the two methods more successfully identified high confidence targets. In Drosophila cells, RBP-APOBEC fusions generated only low numbers of editing sites, comparable to the level of control editing. This was true for two different RBPs, Hrp48 and Thor (Drosophila EIF4E-BP), indicating that STAMP does not work well in Drosophila.

Ecologically relevant stimuli and color memory

Ecologically relevant stimuli were developed as an alternative to Munsell color chips. Colored pictures of familiar objects were used to study color memory. We investigated the typicality of color to particular objects. Contextually typical colors were remembered more accurately than atypical colors were. Moreover, this variable had a stronger effect on memory than focality did. We concluded that memory for ecologically relevant material is more impressed by a color's relation to experience than by its intrinsic properties.

Do the studies on identical twins prove that schizophrenia is genetically inherited?

Ten studies on identical twins reared apart are reviewed to determine if they substantiate a genetic component of schizophrenia. These studies have not eliminated likely social causes of schizophrenia in the twins, and therefore the origins of schizophrenia remain unsolved.

Adherents of the theory that schizophrenia is genetically inherited, point to studies on iden tical twins reared apart as verifying their position. These studies have found several pairs of wins concordant for schizophrenia in which the two individuals were brought up apart from each other. Given this social separation, the explanation that is offered for the concordance is that genetic similarities caused the twins both to become schizophrenic. It is proposed here that none of the studies on identical twins rule out social causes of schizophrenia, and that social causes may very well have been operative.

Ten studies have been reported on identical twins reared apart in which at least one twin was schizophrenic. Of the 27 pairs of twins studied, 14 have been concordant for schizophrenia and 13 have been discordant. The following table summarises the findings (from Rosenthal, 1970; Gottesman and Shields, 1972 and Inouye, 1972).