title: An androgenic gland membrane-anchored gene associated with the crustacean insulin-like androgenic gland hormone.
abstract: Crustacean male sexual differentiation is governed by the androgenic gland (AG) and specifically by the secreted insulin-like AG hormone (IAG), thus far identified in several decapod species including the Australian red claw crayfish Cherax quadricarinatus (termed Cq-IAG). While a few insulin-like AG genes have been identified in crustaceans, other AG-specific genes have not been documented until now. In the present study, we describe the recent identification of a non-IAG AG-specific transcript obtained from the C. quadricarinatus AG cDNA library. This transcript, termed C. quadricarinatus membrane-anchored AG-specific factor (Cq-MAG), was fully sequenced and found to encode a putative product of 189 amino acids including a signal anchoring peptide. Expression of a recombinant GFP fusion protein lacking the signal anchor encoding sequence dramatically affected recombinant protein localization pattern. While the expression of the deleterious fusion protein was observed throughout most of the cell, the native GFP::Cq-MAG fusion protein was observed mainly surrounding the periphery of the nucleus, demonstrating an endoplasmic reticulum (ER)-like localization pattern. Moreover, co-expression of the wild-type Cq-MAG (fused to GFP) and the Cq-IAG hormone revealed that these peptides indeed co-localize. This study is the first to report a protein specifically associated with the insulin-like AG hormone in addition to the finding of another AG-specific transcript in crustaceans. Previous knowledge suggests that insulin/insulin-like factor secretion involves tissue-specific transcripts and membrane-anchored proteins. In this regard, Cq-MAG's tissue specificity, anchoring properties and intracellular co-localization with Cq-IAG suggest that it may play a role in the processing and secretion of this insulin-like AG hormone.
authors.affiliation: The Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
authors.forename: Ohad
authors.initials: O
authors.lastname: Rosen
authors.forename: Rivka
authors.initials: R
authors.lastname: Manor
authors.forename: Simy
authors.initials: S
authors.lastname: Weil
authors.forename: Eliahu D
authors.initials: ED
authors.lastname: Aflalo
authors.forename: Anna
authors.initials: A
authors.lastname: Bakhrat
authors.forename: Uri
authors.initials: U
authors.lastname: Abdu
authors.forename: Amir
authors.initials: A
authors.lastname: Sagi
mesh_terms: D000595:Amino Acid Sequence; D000728:Androgens / Q000378:metabolism*; D000818:Animals; D060829:Arthropod Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D003400:Astacoidea / Q000737:chemistry / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D001483:Base Sequence; D007328:Insulin / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D012733:Sex Differentiation; D014158:Transcription, Genetic
chemical_list: D000728:Androgens; D060829:Arthropod Proteins; D007328:Insulin
keywords: Cq-IAG; Cq-MAG; Crustacea; androgenic gland; co-localization; crayfish; sexual differentiation; signal anchor