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CaM kinase IV regulates lineage commitment and survival of erythroid progenitors in a non-cell-autonomous manner.

Wayman GA, Walters MJ, Kolibaba K, Soderling TR, Christian JL - J. Cell Biol. (2000)

Bottom Line: Here, we show that CaM KIV transcripts are widely distributed during embryogenesis and that strict regulation of CaM KIV activity is essential for normal primitive erythropoiesis.These blood defects are observed even when CaM KIV activity is misregulated only in cells that do not contribute to the erythroid lineage.Thus, proper regulation of CaM KIV activity in nonhematopoietic tissues is essential for the generation of extrinsic signals that enable hematopoietic stem cell commitment to erythroid differentiation and that support the survival of erythroid precursors.

View Article: PubMed Central - PubMed

Affiliation: Vollum Institute, Oregon Health Sciences University, Portland, Oregon 97201-3098, USA.

ABSTRACT
Developmental functions of calmodulin-dependent protein kinase IV (CaM KIV) have not been previously investigated. Here, we show that CaM KIV transcripts are widely distributed during embryogenesis and that strict regulation of CaM KIV activity is essential for normal primitive erythropoiesis. Xenopus embryos in which CaM KIV activity is either upregulated or inhibited show that hematopoietic precursors are properly specified, but few mature erythrocytes are generated. Distinct cellular defects underlie this loss of erythrocytes: inhibition of CaM KIV activity causes commitment of hematopoietic precursors to myeloid differentiation at the expense of erythroid differentiation, on the other hand, constitutive activation of CaM KIV induces erythroid precursors to undergo apoptotic cell death. These blood defects are observed even when CaM KIV activity is misregulated only in cells that do not contribute to the erythroid lineage. Thus, proper regulation of CaM KIV activity in nonhematopoietic tissues is essential for the generation of extrinsic signals that enable hematopoietic stem cell commitment to erythroid differentiation and that support the survival of erythroid precursors.

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Whole-mount in situ analysis of xCaM KIV expression in Xenopus embryos. (A) Animal pole view of a gastrula stage 13 embryo. (B) Dorsal view of a neurula stage 24 embryo. (C) Lateral view of a tailbud stage 34 embryo. (D) Lateral view or transverse sections at the level of the (E) midbrain, (F) hindbrain, and (G) spinal cord of stage 39 tadpoles. Strong staining is noted in portions of the hindbrain (HB), midbrain (MB), Rohon-Beard sensory neurons (R-B), olfactory placode (OP), and cranial nerves (CN) V, VII, and IX.
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Figure 3: Whole-mount in situ analysis of xCaM KIV expression in Xenopus embryos. (A) Animal pole view of a gastrula stage 13 embryo. (B) Dorsal view of a neurula stage 24 embryo. (C) Lateral view of a tailbud stage 34 embryo. (D) Lateral view or transverse sections at the level of the (E) midbrain, (F) hindbrain, and (G) spinal cord of stage 39 tadpoles. Strong staining is noted in portions of the hindbrain (HB), midbrain (MB), Rohon-Beard sensory neurons (R-B), olfactory placode (OP), and cranial nerves (CN) V, VII, and IX.

Mentions: The spatial pattern of expression of CaM KIV was further examined by whole-mount in situ hybridization of digoxygenin-labeled riboprobes to embryos at different stages of development (Fig. 3). This analysis confirmed that CaM KIV transcripts are broadly distributed in early gastrula (Fig. 3 A) through late neurula- (B) stage embryos. In tailbud stage 34 (Fig. 3 C) and tadpole stage 39 (D–G) embryos, CaM KIV transcripts are highly enriched in lateral regions of the midbrain (MB) and hindbrain (HB), the olfactory placode (OP), Rohon-Beard sensory neurons (R-B), and in various cranial nerves, including the opthalmic branch of the trigeminal nerve (CN V), the facial nerve (CN VII), and the glossopharyngeal nerve (CN IX). Although RT-PCR analysis demonstrates that CaM KIV transcripts are present in ventral cells of tailbud-stage embryos (Fig. 2 B), this is not readily apparent by in situ hybridization, most likely because of a low level ubiquitous expression and the fact that ventral cells have a high yolk content that prevents efficient penetration of probes (Lemaire and Gurdon 1994).


CaM kinase IV regulates lineage commitment and survival of erythroid progenitors in a non-cell-autonomous manner.

Wayman GA, Walters MJ, Kolibaba K, Soderling TR, Christian JL - J. Cell Biol. (2000)

Whole-mount in situ analysis of xCaM KIV expression in Xenopus embryos. (A) Animal pole view of a gastrula stage 13 embryo. (B) Dorsal view of a neurula stage 24 embryo. (C) Lateral view of a tailbud stage 34 embryo. (D) Lateral view or transverse sections at the level of the (E) midbrain, (F) hindbrain, and (G) spinal cord of stage 39 tadpoles. Strong staining is noted in portions of the hindbrain (HB), midbrain (MB), Rohon-Beard sensory neurons (R-B), olfactory placode (OP), and cranial nerves (CN) V, VII, and IX.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2169444&req=5

Figure 3: Whole-mount in situ analysis of xCaM KIV expression in Xenopus embryos. (A) Animal pole view of a gastrula stage 13 embryo. (B) Dorsal view of a neurula stage 24 embryo. (C) Lateral view of a tailbud stage 34 embryo. (D) Lateral view or transverse sections at the level of the (E) midbrain, (F) hindbrain, and (G) spinal cord of stage 39 tadpoles. Strong staining is noted in portions of the hindbrain (HB), midbrain (MB), Rohon-Beard sensory neurons (R-B), olfactory placode (OP), and cranial nerves (CN) V, VII, and IX.
Mentions: The spatial pattern of expression of CaM KIV was further examined by whole-mount in situ hybridization of digoxygenin-labeled riboprobes to embryos at different stages of development (Fig. 3). This analysis confirmed that CaM KIV transcripts are broadly distributed in early gastrula (Fig. 3 A) through late neurula- (B) stage embryos. In tailbud stage 34 (Fig. 3 C) and tadpole stage 39 (D–G) embryos, CaM KIV transcripts are highly enriched in lateral regions of the midbrain (MB) and hindbrain (HB), the olfactory placode (OP), Rohon-Beard sensory neurons (R-B), and in various cranial nerves, including the opthalmic branch of the trigeminal nerve (CN V), the facial nerve (CN VII), and the glossopharyngeal nerve (CN IX). Although RT-PCR analysis demonstrates that CaM KIV transcripts are present in ventral cells of tailbud-stage embryos (Fig. 2 B), this is not readily apparent by in situ hybridization, most likely because of a low level ubiquitous expression and the fact that ventral cells have a high yolk content that prevents efficient penetration of probes (Lemaire and Gurdon 1994).

Bottom Line: Here, we show that CaM KIV transcripts are widely distributed during embryogenesis and that strict regulation of CaM KIV activity is essential for normal primitive erythropoiesis.These blood defects are observed even when CaM KIV activity is misregulated only in cells that do not contribute to the erythroid lineage.Thus, proper regulation of CaM KIV activity in nonhematopoietic tissues is essential for the generation of extrinsic signals that enable hematopoietic stem cell commitment to erythroid differentiation and that support the survival of erythroid precursors.

View Article: PubMed Central - PubMed

Affiliation: Vollum Institute, Oregon Health Sciences University, Portland, Oregon 97201-3098, USA.

ABSTRACT
Developmental functions of calmodulin-dependent protein kinase IV (CaM KIV) have not been previously investigated. Here, we show that CaM KIV transcripts are widely distributed during embryogenesis and that strict regulation of CaM KIV activity is essential for normal primitive erythropoiesis. Xenopus embryos in which CaM KIV activity is either upregulated or inhibited show that hematopoietic precursors are properly specified, but few mature erythrocytes are generated. Distinct cellular defects underlie this loss of erythrocytes: inhibition of CaM KIV activity causes commitment of hematopoietic precursors to myeloid differentiation at the expense of erythroid differentiation, on the other hand, constitutive activation of CaM KIV induces erythroid precursors to undergo apoptotic cell death. These blood defects are observed even when CaM KIV activity is misregulated only in cells that do not contribute to the erythroid lineage. Thus, proper regulation of CaM KIV activity in nonhematopoietic tissues is essential for the generation of extrinsic signals that enable hematopoietic stem cell commitment to erythroid differentiation and that support the survival of erythroid precursors.

Show MeSH
Related in: MedlinePlus