Journal: BMC Evolutionary Biology
Article Title: The mammary gland-specific marsupial ELP and eutherian CTI share a common ancestral gene
Figure Lengend Snippet: ELP expression in the tammar mammary gland throughout the reproductive cycle. A. Northern analysis of total RNA (10 μg) extracted from the mammary glands of tammar wallabies during pregnancy (P, Phase 1) and lactation (L, Phase 2A, Phase 2B and Phase 3), from non-sucked (NS) glands and from a virgin female (~220 days of age). Tammar ELP expression was undetected in the virgin gland, minimal during pregnancy (Phase 1) and then induced at parturition and expressed during early lactation (Phase 2A). ELP was down-regulated at mid-lactation (Phase 2B), consistent with [ 13 , 20 , 21 ]. ELP transcripts were not detected in Phase 3. ELP expression also declined postpartum in non-sucked glands. Tammar LGB was used as a positive control for lactation and exhibited a similar expression pattern to ELP , but with LGB expression increased (but not significantly so) during Phases 2B and 3, as reported previously [ 13 , 68 , 69 ]. Ribosomal RNA bands indicate RNA integrity and loading. B. Microarray analysis of the tammar mammary gland [ArrayExpress: E-MTAB-1057] supported the quantitative analysis of Northern blot (data not shown) and microarray data reported by [ 69 ]. Expression of the ELP and LGB milk protein genes and the housekeeping gene GAPDH (glyceraldehyde 3-phosphate dehydrogenase) is depicted as average normalised raw intensity based upon the expression n = 3, 7 and 2 clones on each microarray respectively ± SEM (Additional file 12: Table S5). Whilst ELP (red) and LGB (blue) expression differed during the reproductive cycle, GAPDH (green) expression was constant.
Article Snippet: Glass microarray slides were printed by the Peter MacCallum Cancer Centre Microarray Core Facility, Melbourne, Australia and contained 10,368 tammar cDNA spots which were derived from a commercially prepared (Life Technologies, Rockville, MD, USA), normalised 15,001 tammar mammary gland EST (expressed sequence tag) library.
Techniques: Expressing, Northern Blot, Positive Control, Microarray, Clone Assay