Holling TM et al. (2000), Differential onset of expression of mRNAs encod...

XB-ART-11583

Brain Res Mol Brain Res 2000 Jan 10;751:70-5. doi: 10.1016/s0169-328x(99)00296-x.

Show Gene links Show Anatomy links

Differential onset of expression of mRNAs encoding proopiomelanocortin, prohormone convertases 1 and 2, and granin family members during Xenopus laevis development.

Holling TM , van Herp F , Durston AJ , Martens GJ .

???displayArticle.abstract???
The production of peptide hormones through proteolytic cleavage of prohormones, e.g., proopiomelanocortin (POMC), involves a number of regulated secretory proteins, such as prohormone convertase PC1, PC2 and granin family members, that are co-expressed with the prohormone. Although the expression of these proteins has been well-studied in adult animals, data on their expression during development are limited. We used whole-mount in situ hybridization to visualize POMC mRNA expression in the intermediate and anterior pituitary of Xenopus tadpoles. A more sensitive analysis, namely semi-quantitative reverse-transcription polymerase chain reaction (RT-PCR) on total RNA isolated from Xenopus developmental stages, revealed that the expression of POMC, PC1 and PC2 mRNA commenced at stages 13 (neural plate stage), 15 (neural fold stage) and 19 (neural tube stage), respectively, with a gradual increase in their expression levels during further development. Surprisingly, and in contrast to what holds for POMC and the convertases, mRNAs for secretogranin II and III (SgII, SgIII) and 7B2 were not only expressed during neural development, but could already be detected in unfertilized mature oocytes, the first cleavage stages and in blastula-stage embryos. These granins are thus maternally present in Xenopus embryos suggesting that they may have a role during oogenesis and/or early embryonic development.

???displayArticle.pubmedLink??? 10648889
???displayArticle.link??? Brain Res Mol Brain Res

Species referenced: Xenopus laevis
Genes referenced: hesx1 odc1 pkd2 pomc scg2 scg3

???attribute.lit??? ???displayArticles.show???

	Fig. 1. Whole-mount in situ hybridization with antisense DIG-labeled POMC RNA probe on Xenopus embryos. A. Stage 35, B–C. stage 38 embryo A–B are side views of the embryo, C is a dorsal view.. D. A sagittal section through the pituitary gland of a stage 38 embryo analyzed for POMC expression by whole mount in situ hybridization. Arrows indicate the sites of hybridization. IP: intermediate pituitary, AP: anterior pituitary. Scale bars30 mm.
	Fig. 2. RT-PCR analysis of POMC, PC1, PC2, SgII, SgIII and 7B2 mRNA expression during development of Xenopus laeíis. PCR products were analyzed on agarose gel and stained with ethidium bromide. A representative of three independent experiments is shown. XANF-2 and ODC were used as controls. O: mature unfertilized oocytes, B: adult Xenopus brain, y: no RNA.
	Fig. 3. Expression levels of mRNAs encoding POMC, PC1, PC2, SgII, SgIII, 7B2, XANF-2 and ODC during Xenopus laeíis development determined by semi-quantitative RT-PCR. Levels in arbitrary units, AU. were quantified by densitometric scanning of ethidium bromide stained PCR products see Fig. 2.. Data represent the average of three independently performed experiments with the standard error of the mean S.E.M.. indicated.