The Lhx1-Ldb1 complex interacts with Furry to regulate microRNA expression during pronephric kidney development

Abstract

The molecular events driving specification of the kidney have been well characterized. However, how the initial kidney field size is established, patterned, and proportioned is not well characterized. Lhx1 is a transcription factor expressed in pronephric progenitors and is required for specification of the kidney, but few Lhx1 interacting proteins or downstream targets have been identified. By tandem-affinity purification, we isolated FRY like transcriptional coactivator (Fryl), one of two paralogous genes, fryl and furry (fry), have been described in vertebrates. Both proteins were found to interact with the Ldb1-Lhx1 complex, but our studies focused on Lhx1/Fry functional roles, as they are expressed in overlapping domains. We found that Xenopus embryos depleted of fry exhibit loss of pronephric mesoderm, phenocopying the Lhx1-depleted animals. In addition, we demonstrated a synergism between Fry and Lhx1, identified candidate microRNAs regulated by the pair, and confirmed these microRNA clusters influence specification of the kidney. Therefore, our data shows that a constitutively-active Ldb1-Lhx1 complex interacts with a broadly expressed microRNA repressor, Fry, to establish the kidney field.

Furry is required for cell movements during gastrulation and functionally interacts with NDR1

“…We and others have previously determined that fry is expressed in the involuting mesoderm of the early gastrula, becoming restricted to dorsal tissues and lateral plate mesoderm of neurula, and remaining in somites, notochord, heart, eye, brain and pronephric kidney through tailbud stages 27 , 28 . We investigated in more detail its expression pattern before and during gastrulation.…”

“…Anterior–posterior axis development is the result of early establishment of mesodermal cell fates and morphogenetic movements that contribute to cell rearrangements during gastrulation 1 , 3 , 29 . As Fry has roles in mesoderm development 27 , 28 and depleted embryos exhibited reduced head structures and a shortened axis 27 , we tested the expression of early genes corresponding to different cell subpopulations of the dorsal organizer. At early gastrula stages, the expression domains of orthodenticle homeobox 2 (otx2) 30 and goosecoid (gsc) 31 genes in the presumptive prechordal mesoderm were reduced in fry -MO injected embryos (Fig.…”

“…Fry's role in vertebrate development has only been studied in Xenopus where it was described as a maternally expressed gene 27 . In the early gastrula embryo, fry transcripts are present in the dorsal and ventral tissues and later in the mesoderm and ectoderm derivatives 27 , 28 . Fry function has been associated with the regulation of microRNAs regulating the expression of genes in the axial mesoderm (prechordal mesoderm and chordamesoderm) of the early gastrula and the development of the pronephric kidney 27 , 28 .…”

“…In the early gastrula embryo, fry transcripts are present in the dorsal and ventral tissues and later in the mesoderm and ectoderm derivatives 27 , 28 . Fry function has been associated with the regulation of microRNAs regulating the expression of genes in the axial mesoderm (prechordal mesoderm and chordamesoderm) of the early gastrula and the development of the pronephric kidney 27 , 28 . The study by Goto et al, also showed that Fry has axis-inducing activity resulting in a partial secondary axis when overexpressed in ventral blastomeres 27 .…”

In-depth proteome analysis of more than 12,500 proteins in buffalo mammary epithelial cell line identifies protein signatures for active proliferation and lactation

“…Human isoforms of OPN were reported to impart stemness in MECs 32 . FRY and its paralogue FRYL were suggested to act synergistically in the development and function of kidney 33,34 . The presence of these proteins in our dataset suggests that they may have a potential role during mammary gland morphogenesis in ruminants, which needs further investigation.…”