Baculovirus expression of FIGLA to characterize as a Non-Hormonal Contraceptive Target


The Bill and Melinda Gates Foundation awarded the Structural Genomics Consortium with the SGC Women’s and Children’s Health Initiative in September 2021.  The initiative targets a group of proteins for effective non-hormonal contraceptive agents.  Each target protein will be purified and characterized to screen for possible chemical probes and drug candidates.

SGC-UNC was assigned the target protein FIGLA, factor in germline alpha or folliculogenesis specific BHLH transcription factor.

The target portfolio included egg specific, sperm specific and egg-sperm fusio targets.   FILGA is an egg specific target as it is involved in oocyte maturation.  FIGLA is a germline specific transcription factor implicated in postnatal oocyte-specific gene expression.  FIGLA is located on human chromosome 2p13.3 and it encodes a bHLH protein (1).   FIGLA plays a key regulatory role in the expression of multiple oocyte-specific genes, including those that initiate folliculogenesis and those that encode the zona pellucida (ZP1, ZP2 and ZP3) required for fertilization and early embryonic survival (2).  FIGLA is essential for oocytes to survive and form primordial follicles.

Hypothetical model of FIGLA function in early folliculogenesis:



Plasmids were kindly supplied to us from Alma Seitova and Peter Loppnau at SCG-Toronto.

12 constructs for FIGLA were received.  We chose to start with the FIGLA_FL_BV_his and FILGA_FL_BV_bio for baculovirus expression.

figla plasmids


Purification of FIGLA protein was done using the baculovirus expression system following the SGC protocol:


Medium-Throughput Production of Recombinant Human Proteins: Protein Production in Insect Cells.  Structural Genomics pp95-121, October 12, 2013



FIGLA plasmids were transformed into DH10Bac comp cells and streaked for Blue/White colony detection.  White colonies were detected and purified using Zymo BAC DNA mini prep kit.

Fig 1

Sf9 cells were grown in SFM-900II SFM and transfected for 72hr and 96hr.  P0 virus was used for small scale test expression according to the SGC protocol mentioned above.   Briefly, SF9 cells at a density of 2 x 106 cells/ml were infected with 120ul P0 BV stocks and incubated at 27oC for 66-72hrs (test #1), 144hr (test #2) and 166 hr (test#3).  Cells were pelleted and washed in ice cold PBS, sonicated and lysate was incubated with NiNTA for 1hr at 18oC with shaking at 90rpm.   Lysate was centrifuged and washed before adding Elution buffer.  Samples were removed and run on SDS-PAGE to look for protein by Coomassie stain or antibody detection.

Fig 2

Fig 3

Fig 4


Test expression of FIGLA in the baculovirus expression system did not produce the correct size protein at any of the time intervals tested.    Modifications to this protocol were discussed with the protein expression group and will be tested again.


Thanks to all the candidate champions for their input and support on this project.  Special thanks to Alma Seitova and Peter Loppnau at SGC Toronto for sending us the plasmids and for their help with the baculovirus expression.

Key references


(1)Huntriss J, Gosden R, Hinkins M, Oliver B, Miller D, Rutherford AJ, et al. Isolation, characterization and expression of the human Factor In the Germline alpha (FIGLA) gene in ovarian follicles and oocytes.Mol Hum Reprod. (2002) 8:1087–95. doi: 10.1093/molehr/8.12.1087

(2)Pangas SA, Rajkovic A. Transcriptional regulation of early oogenesis: in search of masters.Hum Reprod Update. (2006) 12:65–76. doi: 10.1093/humupd/dmi033

(3)Soyal SM, Amleh A, Dean J. FIGalpha, a germ cell-specific transcription factor required for ovarian follicle formation.Development. (2000) 127:4645–54. doi: 10.1242/dev.127.21.4645


Medium-Throughput Production of Recombinant Human Proteins: Protein Production in Insect Cells.  Structural Genomics pp95-121, October 12, 2013


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