Table 6.

Evaluation of the myogenic activity of chimeric ascidian MRFs and CiMRF.

		SMYD1			TPM2			TnI
Plasmid	End+	LPH+	Total	End+	LPH+	Total	End+	LPH+	Total
pTTFLacZ	0	0	64	0	0	51	1	1	113
pFCiMRFb	32	8	58	62	32	97	85	11	99
pFHr2Ci	2	0	109	38	29	95	36	28	123
pFPmCi	13	1	71	38	14	70	61	19	121
pFCsCi	17	1	96	43	21	83	47	17	77

Data are the combined totals of at least three independent experiments and are displayed as the number of embryos positive for the expression of the indicated muscle marker anywhere in the head endoderm (End+) or in the lateral posterior of the head only (LPH+). Total refers to the total number of embryos examined, and differs from the sum of End+ and LPH+ by the number of embryos that were negative for expression of the indicated marker in the head. Using Fisher’s exact test (two tailed) to calculate p-values, there were two instances where chimeric MRF plasmids acted similarly to pFCiMRFb (pFPmCi and pFCsCi assayed for TPM2 expression vs. pFCiMFRb; P = 0.2628 and 0.1293, respectively). In all other cases examined, none were deemed as effective as pFCiMRFb at eliciting muscle gene activity in the endoderm (P < 0.01). If LPH+ embryos were included in this analysis of TPM2 expression the differences between embryos electroporated with pFPmCi or pFCsCi and pFCiMRFb were significant (P < 0.0001 for both plasmids vs. pFCiMRFb). Conversely, except for pFHr2Ci, which like the negative control failed to elicit SMYD1 activity anywhere in the head (P = 0.5311 vs. pTTFLacZ), all plasmids stimulated the expression of all muscle markers to an extent greater than pTTFLacZ (P < 0.01).