Spinach plastid genes coding for initiation factor IF-1, ribosomal protein S11 and RNA polymerase α-subunit

摘要

The nucleotide sequence of 2.5 kbp from the cloned Sail fragments 8 and 11 of spinach plastid DNA has been determined. This region was found to encode three open reading frames for hydrophilic polypeptides of 77, 138, and 335 amino acids. Using the computer search algorithm of Lipman and Pearson (Science 227, 1435, 1985),these genes were identified as coding for homologues of E. ooli initiation factor IF-1 (infA), 30S ribosomal protein S11 (rps11), and the α-subunit of DNA-dependent RNA polymerase (rpoA). The spinach plastid gene organization is infA - 381 bp spacer - rps11 - 72 bp spacer -rpoA. The genes are transcribed in vivo and appear to encode functional proteins. These findings imply that plastid chromosomes code for components of the organelle transcription apparatus.