Elshaer Nashwa, Piulachs Maria-Dolors
Institut de Biologia Evolutiva, CSIC-Universitat Pompeu Fabra, Barcelona, 08003, Spain.
Permanent address: Department of Pest Control, Faculty of Agriculture, Zagazig University, Egypt.
Biol Cell. 2015 Aug;107(8):273-85. doi: 10.1111/boc.201500003. Epub 2015 Jun 5.
Epidermal growth factor receptor (EGFR) signalling is crucial for the regulation of multiple developmental processes. Its function in relation to insect oogenesis has been thoroughly studied in the fly Drosophila melanogaster, which possesses ovaries of the highly modified meroistic type. Conversely, studies in other insect species with different ovary types are scarce. We have studied EGFR functions in the oogenesis of the cockroach Blattella germanica, a phylogenetically basal insect with panoistic ovaries.
In this cockroach, depletion of EGFR expression aborts oocyte maturation and prevents oviposition, as affects the distribution of F-actins in the follicular cells of the basal ovarian follicle, which triggers premature apoptosis. In the younger ovarian follicles within the ovariole, depletion of EGFR expression reduces the number of follicular cells, possibly because the Hippo pathway is altered; moreover, the concomitant reduction of Notch expression results in the absence of stalk. Finally, depletion of EGFR determines an increase in the number of germinal cells.
In the panoistic ovary of B. germanica, EGFR plays a role in the control of cell proliferation through interaction with Hippo and Notch pathways.
表皮生长因子受体（EGFR）信号传导对于多种发育过程的调控至关重要。其在昆虫卵子发生中的功能已在果蝇黑腹果蝇中得到深入研究，果蝇拥有高度特化的meroistic型卵巢。相反，在具有不同卵巢类型的其他昆虫物种中的研究却很少。我们研究了EGFR在德国小蠊卵子发生中的功能，德国小蠊是一种具有无滋式卵巢的系统发育基础昆虫。
在这种蟑螂中，EGFR表达的缺失会导致卵母细胞成熟中止并阻止产卵，因为这会影响基础卵巢卵泡滤泡细胞中F-肌动蛋白的分布，从而引发过早凋亡。在卵巢小管内较年轻的卵巢卵泡中，EGFR表达的缺失会减少滤泡细胞的数量，这可能是因为Hippo信号通路发生了改变；此外，Notch表达的同时减少会导致柄的缺失。最后，EGFR的缺失会导致生殖细胞数量增加。
在德国小蠊的无滋式卵巢中，EGFR通过与Hippo和Notch信号通路相互作用，在细胞增殖控制中发挥作用。
