A dual role of lola in Drosophila ovary development: regulating stem cell niche establishment and repressing apoptosis

Abstract

In Drosophila ovary, niche is composed of somatic cells, including terminal filament cells (TFCs), cap cells (CCs) and escort cells (ECs), which provide extrinsic signals to maintain stem cell renewal or initiate cell differentiation. Niche establishment begins in larval stages when terminal filaments (TFs) are formed, but the underlying mechanism for the development of TFs remains largely unknown. Here we report that transcription factor longitudinals lacking (Lola) is essential for ovary morphogenesis. We showed that Lola protein was expressed abundantly in TFCs and CCs, although also in other cells, and lola was required for the establishment of niche during larval stage. Importantly, we found that knockdown expression of lola induced apoptosis in adult ovary, and that lola affected adult ovary morphogenesis by suppressing expression of Regulator of cullins 1b (Roc1b), an apoptosis-related gene that regulates caspase activation during spermatogenesis. These findings significantly expand our understanding of the mechanisms controlling niche establishment and adult oogenesis in Drosophila.

Identification and functional analysis of CG3526 in spermatogenesis of Drosophila melanogaster

“…The w 1118 and C587‐Gal4 fly lines (Zhao et al. , 2022) were maintained in the laboratory. The Ptc‐Gal4 (THJ0201), Nos‐Gal4 (TB00040), UAS‐CG3526 RNAi (TH04130.N), and UAS‐Stat92E RNAi (THU0573) fly lines were obtained from Tsinghua Fly Center in Beijing, China.…”

“…Total RNA was extracted as described previously (Zhao et al. , 2022). The 1 st ‐strand cDNA was synthesized from 1 μg of total RNA using HiFiScript gDNA removal cDNA Synthesis Kit (Cwbiotech, Taizhou, China).…”

“…In our previous study, we performed the transcriptome sequencing of the ovary from lola RNA interference (RNAi) and wild type flies and found that Lola affected adult ovary morphogenesis by suppressing the expression of Regulator of cullins 1b ( Roc1b ) (Zhao et al. , 2022). To better understand the function of lola in the development of gonads, we also performed the transcriptome sequencing of the testis from lola RNAi and wild type flies (data unpublished).…”

Niche formation and function in developing tissue: studies from the Drosophila ovary

“…Zhao et al reported that lola is also essential for TF formation. In lola RNAi ovaries, either no TF stacks are formed or they are disordered [50]. Coincidentally, both lola and bab/ bab2 have a BTB domain, suggesting that this domain may be necessary for TF formation.…”

“…In addition to these signaling pathways, a few genes, including twinstar (tsr), bric-à-brac (bab1/bab2), LIM homeobox transcription factor 1 alpha (Lmx1a) and longitudinals lacking (lola), have been reported to be involved in TFC formation [46][47][48][49][50]. Chen et al found that in tsr mutant ovaries, the TFC number decreased and all TFCs have a rounded appearance.…”