Ubiquitin-encoding mRNA and mRNA recognized by genes encoding ubiquitin-conjugating enzymes are differentially expressed in division-synchronized cultures of Chlamydomonas reinhardtii.
Cells of Chlamydomonas reinhardtii were synchronized by a light/dark illumination cycle of 14:10 h. All cells divided within the first 2 h of the dark period, the synchronization index was calculated as 0.916. RNA was isolated every 2 h and hybridized to 32P-labeled probes encoding (i) ubiquitin from Chlamydomonas reinhardtii (UBM) and (ii) two different ubiquitin-conjugating enzymes from Saccharomyces cerevisiae (UBC2 and UBC3). Sequences with homology to yeast UBC2 and UBC3, which are required for sporulation/DNA repair and G1/S transition in yeast, respectively, were detected in C. reinhardtii. In the algae, the relative abundance of transcripts encoding ubiquitin fusion proteins and UBC2 homologues is most prominent at the end of the light phase and throughout the dark. The highest amount of a putative polyubiquitin encoding transcript was detected during the dark phase of the synchronized culture. A high amount of this transcript is also present during the 8th hour of the light phase which may imply that the transcription of polyubiquitin gene is not only restricted to stress conditions in C. reinhardtii. The relative abundance of transcripts with homology to UBC3 is most pronounced within the light period corresponding to G1 and S phases of the C. reinhardtii cell cycle.
von Kampen
J
J
Botanisches Institut, Technischen Universität, Braunschweig/Federal Republic of Germany.
Wettern
M
M
D000818:Animals; D015152:Blotting, Northern; D015139:Blotting, Southern; D016825:Chlamydomonas reinhardtii / Q000235:genetics* / Q000254:growth & development; D004271:DNA, Fungal / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics; D005800:Genes, Fungal; D012331:RNA, Fungal / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000378:metabolism; D014158:Transcription, Genetic; D014452:Ubiquitins / Q000235:genetics*
D004271:DNA, Fungal; D005656:Fungal Proteins; D012331:RNA, Fungal; D012333:RNA, Messenger; D014452:Ubiquitins