Metallothionein gene expression in embryos of the sea urchinLytechinus pictus

Abstract

The metallothionein (MT) gene LpMT1 of the sea urchin Lytechinus pictus was characterized. The primary transcript of 3042 nucleotides includes four exons, as uniquely observed for other sea urchin MT genes, which are spliced to form a messenger RNA of 605 nucleotides. The deduced LpMT1 protein sequence includes 69 amino acids, more than observed for other MT proteins. For a high level of inducible activity, the LpMT1 promoter requires sequence elements in addition to the canonical regulatory elements identified for mammalian MT promoters. The promoter of the closely related LpMT2 gene is very active in spite of its lack of a distinctive poly(C) element included in a sequence tract required for fully induced activity of the LpMT1 promoter. In contrast to embryos of the sea urchin S. purpuratus in which MT mRNAs are restricted to the aboral ectoderm of uninduced embryos, no spatially preferential accumulation of MT mRNAs in L. pictus embryos was observed. The cis‐acting regulatory elements required for MT gene activity and the spatial specificity of MT gene expression in sea urchin embryos are considered. The LpMT1 and LpMT2 promoters constitute promiscous promoters that can be induced to a high level of activity. Mol. Reprod. Dev. 47:39–46, 1997. © 1997 Wiley‐Liss, Inc.

Regulation of metallothionein genes in the American oyster (Crassostrea virginica): Ontogeny and differential expression in response to different stressors

“…3) is consistent with other studies that demonstrate the fundamental role MTs play in embryogenesis and cellular differentiation (Cserjesi et al, 1997;Angerer et al, 1986;De et al, 1991). CvMT-III is the dominant isoform expressed during early larval development compared to the low basal level of expression of CvMT-I & II and CvMT-IV.…”

Regulation of metallothionein genes in the American oyster (Crassostrea virginica): Ontogeny and differential expression in response to different stressors

“…3) is consistent with other studies that demonstrate the fundamental role MTs play in embryogenesis and cellular differentiation (Cserjesi et al, 1997;Angerer et al, 1986;De et al, 1991). CvMT-III is the dominant isoform expressed during early larval development compared to the low basal level of expression of CvMT-I & II and CvMT-IV.…”

Molecular mechanisms of heavy metal tolerance and evolution in invertebrates

“…At least three MTs were isolated in L. pictus (Cserjesi et al, 1992) of which the LpMT1 promoter was functional in a human cell line, but the human MT(II) promoter was not active when injected in sea-urchin embryos, suggesting that an essential sea-urchin-specific cis-acting element was lacking. No tissue-specific expression of the two MTs (LpMT1 and LpMT2) was observed in this species, but they were Cd inducible (Cserjesi et al, 1997).…”

Embryo, larval, and juvenile staging of Lytechinus pictus from fertilization through sexual maturation

“…The dynamics of the endoplasmic reticulum (ER) membrane at fertilization was first described in the eggs of L. pictus 61 . Some of the first promoters studied in sea urchins were the metal‐responsive elements and regions upstream of metallothionein ( MT1 ) in L. pictus 62,63 . Sea urchins, including L. pictus , were widely used in the early studies of mRNA translation and protein synthesis in early development 64‐66 .…”

“…61 Some of the first promoters studied in sea urchins were the metal-responsive elements and regions upstream of metallothionein (MT1) in L. pictus. 62,63 Sea urchins, including L. pictus, were widely used in the early studies of mRNA translation and protein synthesis in early development. [64][65][66] This included the early work of Nemer and colleagues demonstrating that a diverse array of mRNAs stored in the egg of L. pictus encode the newly synthesized proteins of the early embryo.…”

Regulation of metallothionein genes in the American oyster (Crassostrea virginica): Ontogeny and differential expression in response to different stressors

“…3) is consistent with other studies that demonstrate the fundamental role MTs play in embryogenesis and cellular differentiation (Cserjesi et al, 1997;Angerer et al, 1986;De et al, 1991). CvMT-III is the dominant isoform expressed during early larval development compared to the low basal level of expression of CvMT-I & II and CvMT-IV.…”

Molecular mechanisms of heavy metal tolerance and evolution in invertebrates

“…At least three MTs were isolated in L. pictus (Cserjesi et al, 1992) of which the LpMT1 promoter was functional in a human cell line, but the human MT(II) promoter was not active when injected in sea-urchin embryos, suggesting that an essential sea-urchin-specific cis-acting element was lacking. No tissue-specific expression of the two MTs (LpMT1 and LpMT2) was observed in this species, but they were Cd inducible (Cserjesi et al, 1997).…”

Embryo, larval, and juvenile staging of Lytechinus pictus from fertilization through sexual maturation

“…The dynamics of the endoplasmic reticulum (ER) membrane at fertilization was first described in the eggs of L. pictus 61 . Some of the first promoters studied in sea urchins were the metal‐responsive elements and regions upstream of metallothionein ( MT1 ) in L. pictus 62,63 . Sea urchins, including L. pictus , were widely used in the early studies of mRNA translation and protein synthesis in early development 64‐66 .…”

“…61 Some of the first promoters studied in sea urchins were the metal-responsive elements and regions upstream of metallothionein (MT1) in L. pictus. 62,63 Sea urchins, including L. pictus, were widely used in the early studies of mRNA translation and protein synthesis in early development. [64][65][66] This included the early work of Nemer and colleagues demonstrating that a diverse array of mRNAs stored in the egg of L. pictus encode the newly synthesized proteins of the early embryo.…”

Regulation of metallothionein genes in the American oyster (Crassostrea virginica): Ontogeny and differential expression in response to different stressors

“…3) is consistent with other studies that demonstrate the fundamental role MTs play in embryogenesis and cellular differentiation (Cserjesi et al, 1997;Angerer et al, 1986;De et al, 1991). CvMT-III is the dominant isoform expressed during early larval development compared to the low basal level of expression of CvMT-I & II and CvMT-IV.…”

Molecular mechanisms of heavy metal tolerance and evolution in invertebrates

“…At least three MTs were isolated in L. pictus (Cserjesi et al, 1992) of which the LpMT1 promoter was functional in a human cell line, but the human MT(II) promoter was not active when injected in sea-urchin embryos, suggesting that an essential sea-urchin-specific cis-acting element was lacking. No tissue-specific expression of the two MTs (LpMT1 and LpMT2) was observed in this species, but they were Cd inducible (Cserjesi et al, 1997).…”

Embryo, larval, and juvenile staging of Lytechinus pictus from fertilization through sexual maturation

“…The dynamics of the endoplasmic reticulum (ER) membrane at fertilization was first described in the eggs of L. pictus 61 . Some of the first promoters studied in sea urchins were the metal‐responsive elements and regions upstream of metallothionein ( MT1 ) in L. pictus 62,63 . Sea urchins, including L. pictus , were widely used in the early studies of mRNA translation and protein synthesis in early development 64‐66 .…”

“…61 Some of the first promoters studied in sea urchins were the metal-responsive elements and regions upstream of metallothionein (MT1) in L. pictus. 62,63 Sea urchins, including L. pictus, were widely used in the early studies of mRNA translation and protein synthesis in early development. [64][65][66] This included the early work of Nemer and colleagues demonstrating that a diverse array of mRNAs stored in the egg of L. pictus encode the newly synthesized proteins of the early embryo.…”