Changes in pituitary gene expression between embryonic day 17 and post-hatch day 3.. Gallus gallus

A major research focus in our laboratory is the development of the chicken pituitary gland. As this tissue does not yield sufficient RNA to analyze using cDNA microarrays, mRNA must be amplified by reverse transcription with an oligo-dT primer containing the T7 RNA polymerase promoter site followed by in vitro transcription using T7 RNA polymerase. Therefore, this preliminary study investigating differential gene expression between embryonic day 17, when all the major cell types in the chick anterior pituitary gland have differentiated, and post-hatch day 3 was conducted to verify that amplified antisense RNA could be used in conjunction with our neuroendocrine microarrays containing 5,128 unique cDNAs to detect changes in gene expression. Of the 662 cDNAs that were expressed at significantly different levels between the two ages (P < 0.05, n=3 samples/age), 159 exhibited substantial differences where the higher mean was at least 1.6-fold greater than the lower mean. The majority of the genes (117) increased between e17 and d3. Several genes which may play a role in neuroendocrine development were identified, including many transcription factors, signaling molecules, and morphogeneic factors. Keywords: time course during development (2 ages) Overall design: Three biological replicates each of chicken pituitary embryonic day 17 and post-hatch day 3 amplified antisense RNA were analyzed using neuroendocrine cDNA microarrays in a reference design. Each experimental sample (embryonic day 17 or post-hatch day 3) was labeled with Cy3 and hybridized with an aliquot of the Cy5 reference pool, which was generated from all six RNA samples.