A method for CRISPR/Cas9 mutation of genes in fathead minnow (Pimephales promelas).

Clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 genome editing allows for the disruption or modification of genes in a multitude of model organisms. In the present study, we describe and employ the method for use in the fathead minnow (Pimephales promelas), in part, to assist in the development and validation of adverse outcome pathways (AOPs). The gene coding for an enzyme responsible for melanin production, tyrosinase (tyr), was the initial target chosen for development and assessment of the method since its disruption results in abnormal pigmentation, a phenotype obvious within 3-4 d after injection of fathead minnow embryos.

PIN6 is required for nectary auxin response and short stamen development.

The PIN family of proteins is best known for its involvement in polar auxin transport and tropic responses. PIN6 (At1g77110) is one of the remaining PIN family members in Arabidopsis thaliana to which a biological function has not yet been ascribed. Here we report that PIN6 is a nectary-enriched gene whose expression level is positively correlated with total nectar production in Arabidopsis, and whose function is required for the proper development of short stamens.

Recent developments in factor-facilitated ribosome assembly.

Escherichia coli ribosomal subunits can be reconstituted in vitro under highly optimized conditions. These reconstitution systems have proven invaluable for the study of ribosomal subunit assembly. While E.

Demonstration of the role of the DnaK chaperone system in assembly of 30S ribosomal subunits using a purified in vitro system.

Recently, there has been controversy regarding the ability of the DnaK chaperone system to facilitate Escherichia coli 30S subunit assembly at otherwise nonpermissive conditions. Here, we present additional data indicating that purified DnaK chaperone assembled 30S subunits are functional. Additionally, explanations for reported differences are discussed.

The DnaK chaperone system facilitates 30S ribosomal subunit assembly.

Functional Escherichia coli 30S ribosomal subunits can be reconstituted in vitro. However, slow kinetics and sharp temperature dependence suggest additional assembly factors are present in vivo. Extract activation of in vitro assembly results in association of DnaK/hsp70 chaperone components with pre-30S particles.