(
A) modEncode expression profiles of mRNAs encoding Elba1 and Elba3. As indicated in the diagram,
elba1 (CG12205) and
elba3 (CG15634) are transcribed in opposite directions and are separated from each other by sequences encoding much of the CG11929 open reading frame
http://flybase.org/reports/FBgn0000227.html/,
http://flybase.org/reports/FBgn0031621.html. As seen in the Northerns, there is little or no maternal deposition of
elba1 or
elba3 mRNAs. These two genes are not expressed until the mid-blastula transition and the highest levels of
elba1 and
elba3 mRNAs are found in 2–4 hr embryos. Relatively high levels of both mRNAs are found in 4–6 hr embryos and then both largely but not completely disappear during the remainder of embryogenesis. In our Northern experiments transcript levels also drop dramatically after 6 hr, but in older embryos both
elba1 and
elba3 are detected again. However, it is likely that the amounts of
elba1 and
elba3 in these later stages are overestimated in our experiments. Our gels were overloaded, and transfer of the two
elba mRNAs (which migrate very near the bottom of the rRNA band) in the 2–4 hr samples does not appear to be as efficient as it is at later stages when their levels are greatly reduced. The presence of only quite low levels of
elba1 and
elba3 mRNAs at these later stages would be consistent with the modEncode data. (
B) modEncode expression profiles of mRNAs encoding Elba2 and Insv. Like
elba1 and
elba3,
elba2/CG9883 and
insensitive/CG3227 are closely linked and transcribed in opposite orientations. As seen in our Northern experiments, the modEncode temporal expression patterns of the mRNAs encoding these two proteins are quite different from that of
elba1 and
elba3
http://flybase.org/reports/FBgn0031434.html/,
http://flybase.org/reports/FBgn0031435.html. Both are maternally deposited and high levels are present throughout embryogenesis. Also unlike
elba1 and
elba3, both transcripts are expressed at later stages of development.