Figure 1.

Chlamy 1 binds specifically to the UG-repeat region of the lbp 3′-UTR. (A) Map of in vitro transcripts covering various parts of the lbp 3′-UTR. The shaded bar shows the location of the UG-repeat. The dotted line indicates the deletion of a 48-nt long region of the lbp 3′-UTR. The ladders show the 22-mer oligonucleotide Ol hybridized to the BglI transcript. (B and C) Autoradiograms of mobility-shift assays using the ³²P-labeled BglI transcript or its hybrid (RNA BglI-Ol) in the presence of poly(G) as nonspecific competitor RNA. For the binding reaction, the samples were incubated with Chlamydomonas crude extracts from the night period (LD 14). In some cases, specific cold competitor RNAs (XbaI and XbaI⁻UG transcripts) were added to the binding reaction up to a 20-fold excess. One lane (RNA BglI) always demonstrates the mobility of the transcript alone.