. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 'r^I *<• * 4*. * * \m Figure 5. Two-dimensional protein gel analysis of in two-translated RNA with 35S-methionine reveal changes in gene expression during takeover. Panel A depicts a colony at the onset of a new blastogenic cycle (stage A), whereas panel B is from a colony in early takeover (3 h post-onset). The circled spots in panel A represent transcripts that are repressed in the early stages of takeover. The arrows in panels A and B depict a representative polypeptide whose mRNA is down-regulated during takeover. Con
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 'r^I *<• * 4*. * * \m Figure 5. Two-dimensional protein gel analysis of in two-translated RNA with 35S-methionine reveal changes in gene expression during takeover. Panel A depicts a colony at the onset of a new blastogenic cycle (stage A), whereas panel B is from a colony in early takeover (3 h post-onset). The circled spots in panel A represent transcripts that are repressed in the early stages of takeover. The arrows in panels A and B depict a representative polypeptide whose mRNA is down-regulated during takeover. Conversely, the circled spots in panel B are transcripts that appear to be induced de nova during takeover. Abbreviations: SDS. sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) dimension; IEF, isoelectric focusing di- mension. by Kumar et al. (1988). The presence of contaminating pigments markedly altered OD:W)/28o ratios, presumably by absorbing in the range that is optimal for nucleic acids (, 260 nm). In support of this hypothesis, we have re- cently observed that pigment cells from live colonies are fluorescent under ultraviolet light (, unpub. obs.). Northern blot analysis with cesium-chloride-purified material further revealed that the RNA was not degraded by ribonuclease activity present during zooid regression. Previous studies have cautioned that isolation of intact RNA molecules from dying tissues can be significantly impeded by ribonucleases (Cidlowski, 1982; Owens et ai, 1991). In addition, all colonial ascidian species reported in this paper (Botryllus schlosseri from the East and West coasts, Botryloides diegense, and Diplosoma macdonaldii) expressed two poly-A* transcripts of and kb in length that hybridized to a cytoplasmic cDNA clone from Styela clava. This was in contrast to the single kb- message found in the solitary ascidian Mo/gula manhal- tensis. The significance of two mRNAs in colonial ascid- ians is unclear, alt
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
